This document discusses enzymes, cofactors, and enzyme kinetics. It defines prosthetic groups as molecules that are tightly bound to enzymes and participate in catalysis. Cofactors interact reversibly with enzymes or substrates to facilitate reactions. Coenzymes serve as recyclable carriers of chemical groups between enzymes. The Michaelis-Menten equation describes enzyme kinetics, relating reaction rate to substrate concentration. There are three main types of reversible enzyme inhibition - competitive, uncompetitive, and noncompetitive - which differ in how they affect the enzyme-substrate complex and influence kinetic parameters like Km and Vmax.
CHEMICAL KINETICS AND ENZYMES B23350B,B223081B,B224645B.pptxNyafesaFlorence
This document discusses chemical kinetics and enzyme kinetics. It defines enzymes as biological catalysts that speed up chemical reactions without being used up in the process. The document describes how enzymes lower the activation energy of reactions and explains the mechanisms of enzyme action, including the lock and key and induced fit hypotheses. It also discusses Michaelis-Menten kinetics and how various factors like temperature, pH, cofactors, and inhibitors can affect the rate of enzyme activity. Allosteric enzymes are defined as having additional binding sites for effector molecules.
Enzymes are protein catalysts that accelerate biochemical reactions without being consumed. They are specific, catalytic, reversible, and sensitive to temperature and pH changes. Enzymes lower the activation energy of reactions. The active site of an enzyme binds specifically to substrates. Some enzymes require cofactors like metal ions or coenzymes to function. Enzyme kinetics examines factors that influence reaction rates like substrate concentration. Michaelis-Menten kinetics describes the reversible binding of enzymes and substrates to form enzyme-substrate complexes. Enzyme inhibitors decrease catalytic activity by binding to the active site or elsewhere on the enzyme.
1. Enzymes are protein catalysts that accelerate biochemical reactions in living cells.
2. They are classified based on the type of reaction they catalyze such as oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
3. Enzyme activity is affected by factors like pH, temperature, and inhibitors. Competitive and non-competitive inhibitors bind at the active site or other regions respectively.
Introduction, Nomenclature of enzymes, Classification of enzymes on the basis of site of action, on the reaction of catalysis and Classification depends upon substrates on they which act, Specificity of Enzymes, Active Site of An Enzyme: 1. Lock-key model 2. Induce fit model, Factors Affecting Enzymes Reaction, Enzyme 1.Inhibition Competitive inhibition, 2. Non-Competitive inhibition, Isoenzymes, Allosteric Enzymes, Co-Factors, Turnover Number of An Enzyme, Pharmaceutical Importance Of Enzymes,
This document provides an overview of enzymes including their structure, function, classification, and regulation. Some key points:
- Enzymes are biological catalysts that lower the activation energy of chemical reactions and speed up metabolic processes without being consumed. They accelerate reactions by lowering the energy barrier between reactants and products.
- Enzymes have high specificity, only catalyzing one or a few chemical reactions. They are classified based on the type of chemical reaction they catalyze.
- Many enzymes require cofactors like metal ions or organic coenzymes to function. The apoenzyme combines with its cofactor to form the active holoenzyme.
- Enzyme activity is regulated through controlling availability,
This document discusses enzyme kinetics and the mechanisms of enzyme catalysis. It begins with definitions of key terms like enzyme and catalysis. It then describes classification of enzymes and the structure of active sites. The mechanisms of enzyme catalysis include acid-base, covalent, and metal ion catalysis. It also discusses models of enzyme-substrate binding like lock-and-key and induced fit. Kinetics concepts covered include Michaelis-Menten kinetics, Lineweaver-Burk plots, and factors affecting reaction rates like temperature and pH. Finally, it describes reversible and irreversible inhibition and different types of inhibitors.
1. The document discusses enzyme kinetics and the factors that affect it, including concentration of enzyme and substrate, temperature, pH, product concentration, and activators.
2. It also covers enzyme inhibition, describing reversible inhibition as competitive or non-competitive, and irreversible inhibition.
3. Key concepts explained are Michaelis-Menten kinetics, the Michaelis constant Km, Lineweaver-Burk plots, and the effects of various factors on the reaction rate.
Enzymes are protein catalysts found in cells and tissues. They are responsible for chemical reactions in the body and can be detected in serum to diagnose diseases. Increased enzyme levels in serum may indicate tissue damage or certain disease states. Common enzymes measured include alkaline phosphatase, acid phosphatase, amylase, lipase, SGPT and SGOT which can help diagnose diseases of the bones, prostate, pancreas and liver. Enzymes function as biological catalysts by lowering the activation energy of reactions and increasing their rates without being consumed in the process. They are highly specific and their activity can be affected by factors like pH, temperature, substrate and inhibitor concentrations.
CHEMICAL KINETICS AND ENZYMES B23350B,B223081B,B224645B.pptxNyafesaFlorence
This document discusses chemical kinetics and enzyme kinetics. It defines enzymes as biological catalysts that speed up chemical reactions without being used up in the process. The document describes how enzymes lower the activation energy of reactions and explains the mechanisms of enzyme action, including the lock and key and induced fit hypotheses. It also discusses Michaelis-Menten kinetics and how various factors like temperature, pH, cofactors, and inhibitors can affect the rate of enzyme activity. Allosteric enzymes are defined as having additional binding sites for effector molecules.
Enzymes are protein catalysts that accelerate biochemical reactions without being consumed. They are specific, catalytic, reversible, and sensitive to temperature and pH changes. Enzymes lower the activation energy of reactions. The active site of an enzyme binds specifically to substrates. Some enzymes require cofactors like metal ions or coenzymes to function. Enzyme kinetics examines factors that influence reaction rates like substrate concentration. Michaelis-Menten kinetics describes the reversible binding of enzymes and substrates to form enzyme-substrate complexes. Enzyme inhibitors decrease catalytic activity by binding to the active site or elsewhere on the enzyme.
1. Enzymes are protein catalysts that accelerate biochemical reactions in living cells.
2. They are classified based on the type of reaction they catalyze such as oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
3. Enzyme activity is affected by factors like pH, temperature, and inhibitors. Competitive and non-competitive inhibitors bind at the active site or other regions respectively.
Introduction, Nomenclature of enzymes, Classification of enzymes on the basis of site of action, on the reaction of catalysis and Classification depends upon substrates on they which act, Specificity of Enzymes, Active Site of An Enzyme: 1. Lock-key model 2. Induce fit model, Factors Affecting Enzymes Reaction, Enzyme 1.Inhibition Competitive inhibition, 2. Non-Competitive inhibition, Isoenzymes, Allosteric Enzymes, Co-Factors, Turnover Number of An Enzyme, Pharmaceutical Importance Of Enzymes,
This document provides an overview of enzymes including their structure, function, classification, and regulation. Some key points:
- Enzymes are biological catalysts that lower the activation energy of chemical reactions and speed up metabolic processes without being consumed. They accelerate reactions by lowering the energy barrier between reactants and products.
- Enzymes have high specificity, only catalyzing one or a few chemical reactions. They are classified based on the type of chemical reaction they catalyze.
- Many enzymes require cofactors like metal ions or organic coenzymes to function. The apoenzyme combines with its cofactor to form the active holoenzyme.
- Enzyme activity is regulated through controlling availability,
This document discusses enzyme kinetics and the mechanisms of enzyme catalysis. It begins with definitions of key terms like enzyme and catalysis. It then describes classification of enzymes and the structure of active sites. The mechanisms of enzyme catalysis include acid-base, covalent, and metal ion catalysis. It also discusses models of enzyme-substrate binding like lock-and-key and induced fit. Kinetics concepts covered include Michaelis-Menten kinetics, Lineweaver-Burk plots, and factors affecting reaction rates like temperature and pH. Finally, it describes reversible and irreversible inhibition and different types of inhibitors.
1. The document discusses enzyme kinetics and the factors that affect it, including concentration of enzyme and substrate, temperature, pH, product concentration, and activators.
2. It also covers enzyme inhibition, describing reversible inhibition as competitive or non-competitive, and irreversible inhibition.
3. Key concepts explained are Michaelis-Menten kinetics, the Michaelis constant Km, Lineweaver-Burk plots, and the effects of various factors on the reaction rate.
Enzymes are protein catalysts found in cells and tissues. They are responsible for chemical reactions in the body and can be detected in serum to diagnose diseases. Increased enzyme levels in serum may indicate tissue damage or certain disease states. Common enzymes measured include alkaline phosphatase, acid phosphatase, amylase, lipase, SGPT and SGOT which can help diagnose diseases of the bones, prostate, pancreas and liver. Enzymes function as biological catalysts by lowering the activation energy of reactions and increasing their rates without being consumed in the process. They are highly specific and their activity can be affected by factors like pH, temperature, substrate and inhibitor concentrations.
1) The document discusses enzyme kinetics and the Michaelis-Menten model of enzyme kinetics.
2) It introduces key concepts such as the Michaelis constant Km and maximum velocity Vmax, and derives the Michaelis-Menten equation relating substrate concentration, reaction rate, Km and Vmax.
3) It also discusses factors that affect enzyme activity such as temperature, pH, and enzyme inhibitors, distinguishing between competitive, uncompetitive, and noncompetitive inhibition.
The document discusses microbial metabolism and various metabolic pathways and processes. It describes catabolic reactions that break down nutrients and anabolic reactions that synthesize cellular components. Central to metabolism are enzymes, which lower activation energy for reactions. Metabolic pathways generate ATP through oxidative phosphorylation or substrate-level phosphorylation. The main energy-generating pathways include glycolysis, the Krebs cycle, and the electron transport chain.
1. The document discusses the structure, properties, and mechanisms of enzyme action.
2. It describes how enzymes are classified and named based on their reactions.
3. Key factors that affect enzyme activity like pH, temperature, inhibitors, and cofactors are explained.
Enzymes lower the activation energy of reactions by several mechanisms:
1. Enzymes orient the substrate in a strained transition state that more closely resembles the activation energy.
2. Metal ions and cofactors in metalloenzymes help orient substrates for reaction.
3. Specific amino acids in the active site preferentially bind to and stabilize the higher energy transition state.
4. Bringing substrates close together in multienzyme complexes or keeping reaction intermediates channeled increases reaction rates.
Enzymes mechanism of action, their specificity types, active center structure and action, inhibitor types, fisher and Koshlend theory are presented. Enzymes classification, a new class of enzymes discovered recently, detailed explanation of each class reaction types is presented as well
This document summarizes key concepts about enzymes and cell biology:
- Enzymes are proteins that speed up biochemical reactions by lowering their activation energy and catalyzing the conversion of substrates to products. They have specific active sites that bind substrates.
- Factors like pH, temperature, substrate/enzyme concentrations can affect the rate of enzymatic reactions by impacting enzyme structure and activity. Deviations from optimal conditions can cause enzymes to denature.
- Coenzymes are non-protein molecules like vitamins that help enzymes catalyze reactions by binding to them.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They speed up reactions via an active site where substrates bind. Enzyme activity depends on structure and is highly specific. Factors like temperature, pH, substrate and enzyme concentration can affect reaction rate. Enzymes use various mechanisms like lock-and-key and induced fit to catalyze reactions. Inhibition studies help understand metabolic pathways and develop drugs. There are three main types of reversible inhibition - competitive, non-competitive, and uncompetitive - which are distinguished by their effects on Km and Vmax values.
introduction to medical enzymology class 2Ogunsina1
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They speed up reactions via an active site where substrates bind. Enzyme activity depends on structure and is highly specific. Factors like temperature, pH, substrate and enzyme concentration can affect reaction rate. Enzymes use various mechanisms like lock-and-key and induced fit to catalyze reactions. Inhibition studies help understand metabolic pathways and develop drugs. There are three main types of reversible inhibition - competitive, non-competitive, and uncompetitive - which are distinguished by their effects on Km and Vmax values.
This document discusses enzyme kinetics and regulation. It begins by defining enzymes as proteins that catalyze chemical reactions in cells. Enzymes have specific active sites that bind substrates and use mechanisms like cofactors and induced fit to lower activation energy. Reaction rates follow Michaelis-Menten kinetics and can be regulated through feedback inhibition, allosteric modulation, covalent modification like phosphorylation, and proteolytic cleavage of zymogens. The document also describes different types of reversible and irreversible enzyme inhibition.
This document provides an overview of enzymes and metabolism. It defines enzymes as proteins that catalyze chemical reactions and discusses the lock-and-key and induced-fit models of enzyme action. It also explains factors that influence enzyme activity such as pH and temperature, and describes the roles of coenzymes and enzyme inhibitors.
This document discusses the effects of various factors on enzyme activity. It describes how raising the temperature increases reaction rates by increasing kinetic energy until the enzyme denatures. Most human enzymes are stable up to 35-40°C while thermophilic bacterial enzymes can withstand over 100°C. It also discusses how pH, substrate concentration, enzyme concentration, product concentration, and inhibitors like competitive and noncompetitive inhibitors affect reaction rates. Competitive inhibitors bind the active site while noncompetitive inhibitors bind elsewhere and decrease Vmax. Examples of drug inhibitors are also provided.
Enzymes catalyze chemical reactions by reducing the activation energy needed for the reaction to occur. They do this using several mechanisms including acid-base catalysis, covalent bond formation, and metal ion catalysis. Enzymes are also able to increase reaction rates by properly orienting substrates. Enzyme activity can be inhibited through various reversible and irreversible mechanisms such as competitive inhibition where an inhibitor binds to the active site, and suicide inhibition where the inhibitor is converted by the enzyme into a tightly-binding form. The Michaelis-Menten model and Lineweaver-Burk plots are commonly used to study enzyme kinetics and inhibition types.
The document summarizes key concepts in cell biology related to enzymes. It defines important terms like metabolism, enzyme, substrate, and coenzyme. It describes the roles of enzymes in biochemical reactions and factors that affect their activity, such as pH, temperature, substrate concentration, and inhibitors. Lastly, it discusses experimental design and the scientific method.
This document provides an overview of enzymes and how they catalyze biochemical reactions. It discusses that enzymes are proteins that lower the activation energy of reactions, increasing reaction rates tremendously without affecting equilibrium. Enzymes have evolved to be highly specific for their substrates. Their active sites are complementary in shape to transition states, allowing enzymes to stabilize developing charges and bond rearrangements. Binding energy released upon substrate binding offsets the energy required to reach transition states, reducing the activation energy barrier.
Increasingly, the global food system is under strain, with an increase in the prevalence of polarised obesity and poverty, and increased dependence on chemical fertilizer and pesticides, poor quality foods, environmental degradation, and the loss of biodiversity. As such, many practices are being revised and regenerated. These practices are informed by biochemistry.
Biochemistry is used to enhance plant growth, yield, and quality as a consequence of optimizing fertilizer components. Crop improvement has also been improved by way of increased tolerance to biotic and abiotic stresses, alongside augmented nutritional value.
With knowledge of the mechanism of action of fertilizers, such as nitrates, the use of fertilizer can be optimized to improve plant growth quality. An example of this is the increasing use of biochemical fertilizers including nitrogen fixes, phosphorus potassium, sulfur solubilizers, and various fungi such as mycorrhiza, and Trichoderma, as well as small molecular iron chelators called siderophores that are produced by microbes.
This is thought to ameliorate the effect of intense use of chemical fertilizers, which cause water contamination, depleted nutrients, and soul deterioration.
Biochemistry plays an important role in nutrition and health and is considered to be a powerful unsustainable tool for the improvement of health, reduction of poverty, and hunger in the world. Through the use of sustainable biochemistry, the commercialization of biochemical techniques is considered to be a powerful way of reducing brook global poverty and hunger and improving nutritional delivery across the world.
Increasingly, the global food system is under strain, with an increase in the prevalence of polarised obesity and poverty, and increased dependence on chemical fertilizer and pesticides, poor quality foods, environmental degradation, and the loss of biodiversity. As such, many practices are being revised and regenerated. These practices are informed by biochemistry.
Biochemistry is used to enhance plant growth, yield, and quality as a consequence of optimizing fertilizer components. Crop improvement has also been improved by way of increased tolerance to biotic and abiotic stresses, alongside augmented nutritional value.
With knowledge of the mechanism of action of fertilizers, such as nitrates, the use of fertilizer can be optimized to improve plant growth quality. An example of this is the increasing use of biochemical fertilizers including nitrogen fixes, phosphorus potassium, sulfur solubilizers, and various fungi such as mycorrhiza, and Trichoderma, as well as small molecular iron chelators called siderophores that are produced by microbes.
This is thought to ameliorate the effect of intense use of chemical fertilizers, which cause water contamination, depleted nutrients, and soul deterioration.
Biochemistry plays an important role in nutrition and health and is considered to be a powerful unsustainable tool for the improvement of health, reduction of poverty, and hunger in the world. Through the use of sustainable biochemistry, the commercialization of biochemical techniques is considered to be a powerful way of reducing brook global poverty and hunger and improving nutritional delivery across the world.
Enzyme catalysed reactions, enzyme kinetics and it’s mechanism of action.MdNazmulIslamTanmoy
Enzymes are protein catalysts that regulate chemical reactions in living organisms. They accelerate reactions by lowering the activation energy of transition states through interactions with substrates. Enzymes are classified based on the type of reaction they catalyze, such as oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Enzyme kinetics follow the Michaelis-Menten model where the enzyme-substrate complex breaks down into products. The catalytic activity of enzymes is explained by thermodynamic changes in transition states and specific interactions between the enzyme and substrate at its active site.
1) The document discusses enzyme kinetics and the Michaelis-Menten model of enzyme kinetics.
2) It introduces key concepts such as the Michaelis constant Km and maximum velocity Vmax, and derives the Michaelis-Menten equation relating substrate concentration, reaction rate, Km and Vmax.
3) It also discusses factors that affect enzyme activity such as temperature, pH, and enzyme inhibitors, distinguishing between competitive, uncompetitive, and noncompetitive inhibition.
The document discusses microbial metabolism and various metabolic pathways and processes. It describes catabolic reactions that break down nutrients and anabolic reactions that synthesize cellular components. Central to metabolism are enzymes, which lower activation energy for reactions. Metabolic pathways generate ATP through oxidative phosphorylation or substrate-level phosphorylation. The main energy-generating pathways include glycolysis, the Krebs cycle, and the electron transport chain.
1. The document discusses the structure, properties, and mechanisms of enzyme action.
2. It describes how enzymes are classified and named based on their reactions.
3. Key factors that affect enzyme activity like pH, temperature, inhibitors, and cofactors are explained.
Enzymes lower the activation energy of reactions by several mechanisms:
1. Enzymes orient the substrate in a strained transition state that more closely resembles the activation energy.
2. Metal ions and cofactors in metalloenzymes help orient substrates for reaction.
3. Specific amino acids in the active site preferentially bind to and stabilize the higher energy transition state.
4. Bringing substrates close together in multienzyme complexes or keeping reaction intermediates channeled increases reaction rates.
Enzymes mechanism of action, their specificity types, active center structure and action, inhibitor types, fisher and Koshlend theory are presented. Enzymes classification, a new class of enzymes discovered recently, detailed explanation of each class reaction types is presented as well
This document summarizes key concepts about enzymes and cell biology:
- Enzymes are proteins that speed up biochemical reactions by lowering their activation energy and catalyzing the conversion of substrates to products. They have specific active sites that bind substrates.
- Factors like pH, temperature, substrate/enzyme concentrations can affect the rate of enzymatic reactions by impacting enzyme structure and activity. Deviations from optimal conditions can cause enzymes to denature.
- Coenzymes are non-protein molecules like vitamins that help enzymes catalyze reactions by binding to them.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They speed up reactions via an active site where substrates bind. Enzyme activity depends on structure and is highly specific. Factors like temperature, pH, substrate and enzyme concentration can affect reaction rate. Enzymes use various mechanisms like lock-and-key and induced fit to catalyze reactions. Inhibition studies help understand metabolic pathways and develop drugs. There are three main types of reversible inhibition - competitive, non-competitive, and uncompetitive - which are distinguished by their effects on Km and Vmax values.
introduction to medical enzymology class 2Ogunsina1
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They contain an active site where substrates bind and reactions occur. Enzyme activity depends on factors like temperature, pH, substrate and enzyme concentration, and can be inhibited by certain substances. The Michaelis-Menten model describes how reaction rate varies with substrate concentration, following saturation kinetics. Different types of inhibition alter the kinetic parameters like Km and Vmax in distinct ways that can be visualized through double reciprocal plots.
Enzymes are globular proteins that function as biological catalysts, lowering the activation energy of chemical reactions without being changed themselves. They speed up reactions via an active site where substrates bind. Enzyme activity depends on structure and is highly specific. Factors like temperature, pH, substrate and enzyme concentration can affect reaction rate. Enzymes use various mechanisms like lock-and-key and induced fit to catalyze reactions. Inhibition studies help understand metabolic pathways and develop drugs. There are three main types of reversible inhibition - competitive, non-competitive, and uncompetitive - which are distinguished by their effects on Km and Vmax values.
This document discusses enzyme kinetics and regulation. It begins by defining enzymes as proteins that catalyze chemical reactions in cells. Enzymes have specific active sites that bind substrates and use mechanisms like cofactors and induced fit to lower activation energy. Reaction rates follow Michaelis-Menten kinetics and can be regulated through feedback inhibition, allosteric modulation, covalent modification like phosphorylation, and proteolytic cleavage of zymogens. The document also describes different types of reversible and irreversible enzyme inhibition.
This document provides an overview of enzymes and metabolism. It defines enzymes as proteins that catalyze chemical reactions and discusses the lock-and-key and induced-fit models of enzyme action. It also explains factors that influence enzyme activity such as pH and temperature, and describes the roles of coenzymes and enzyme inhibitors.
This document discusses the effects of various factors on enzyme activity. It describes how raising the temperature increases reaction rates by increasing kinetic energy until the enzyme denatures. Most human enzymes are stable up to 35-40°C while thermophilic bacterial enzymes can withstand over 100°C. It also discusses how pH, substrate concentration, enzyme concentration, product concentration, and inhibitors like competitive and noncompetitive inhibitors affect reaction rates. Competitive inhibitors bind the active site while noncompetitive inhibitors bind elsewhere and decrease Vmax. Examples of drug inhibitors are also provided.
Enzymes catalyze chemical reactions by reducing the activation energy needed for the reaction to occur. They do this using several mechanisms including acid-base catalysis, covalent bond formation, and metal ion catalysis. Enzymes are also able to increase reaction rates by properly orienting substrates. Enzyme activity can be inhibited through various reversible and irreversible mechanisms such as competitive inhibition where an inhibitor binds to the active site, and suicide inhibition where the inhibitor is converted by the enzyme into a tightly-binding form. The Michaelis-Menten model and Lineweaver-Burk plots are commonly used to study enzyme kinetics and inhibition types.
The document summarizes key concepts in cell biology related to enzymes. It defines important terms like metabolism, enzyme, substrate, and coenzyme. It describes the roles of enzymes in biochemical reactions and factors that affect their activity, such as pH, temperature, substrate concentration, and inhibitors. Lastly, it discusses experimental design and the scientific method.
This document provides an overview of enzymes and how they catalyze biochemical reactions. It discusses that enzymes are proteins that lower the activation energy of reactions, increasing reaction rates tremendously without affecting equilibrium. Enzymes have evolved to be highly specific for their substrates. Their active sites are complementary in shape to transition states, allowing enzymes to stabilize developing charges and bond rearrangements. Binding energy released upon substrate binding offsets the energy required to reach transition states, reducing the activation energy barrier.
Increasingly, the global food system is under strain, with an increase in the prevalence of polarised obesity and poverty, and increased dependence on chemical fertilizer and pesticides, poor quality foods, environmental degradation, and the loss of biodiversity. As such, many practices are being revised and regenerated. These practices are informed by biochemistry.
Biochemistry is used to enhance plant growth, yield, and quality as a consequence of optimizing fertilizer components. Crop improvement has also been improved by way of increased tolerance to biotic and abiotic stresses, alongside augmented nutritional value.
With knowledge of the mechanism of action of fertilizers, such as nitrates, the use of fertilizer can be optimized to improve plant growth quality. An example of this is the increasing use of biochemical fertilizers including nitrogen fixes, phosphorus potassium, sulfur solubilizers, and various fungi such as mycorrhiza, and Trichoderma, as well as small molecular iron chelators called siderophores that are produced by microbes.
This is thought to ameliorate the effect of intense use of chemical fertilizers, which cause water contamination, depleted nutrients, and soul deterioration.
Biochemistry plays an important role in nutrition and health and is considered to be a powerful unsustainable tool for the improvement of health, reduction of poverty, and hunger in the world. Through the use of sustainable biochemistry, the commercialization of biochemical techniques is considered to be a powerful way of reducing brook global poverty and hunger and improving nutritional delivery across the world.
Increasingly, the global food system is under strain, with an increase in the prevalence of polarised obesity and poverty, and increased dependence on chemical fertilizer and pesticides, poor quality foods, environmental degradation, and the loss of biodiversity. As such, many practices are being revised and regenerated. These practices are informed by biochemistry.
Biochemistry is used to enhance plant growth, yield, and quality as a consequence of optimizing fertilizer components. Crop improvement has also been improved by way of increased tolerance to biotic and abiotic stresses, alongside augmented nutritional value.
With knowledge of the mechanism of action of fertilizers, such as nitrates, the use of fertilizer can be optimized to improve plant growth quality. An example of this is the increasing use of biochemical fertilizers including nitrogen fixes, phosphorus potassium, sulfur solubilizers, and various fungi such as mycorrhiza, and Trichoderma, as well as small molecular iron chelators called siderophores that are produced by microbes.
This is thought to ameliorate the effect of intense use of chemical fertilizers, which cause water contamination, depleted nutrients, and soul deterioration.
Biochemistry plays an important role in nutrition and health and is considered to be a powerful unsustainable tool for the improvement of health, reduction of poverty, and hunger in the world. Through the use of sustainable biochemistry, the commercialization of biochemical techniques is considered to be a powerful way of reducing brook global poverty and hunger and improving nutritional delivery across the world.
Enzyme catalysed reactions, enzyme kinetics and it’s mechanism of action.MdNazmulIslamTanmoy
Enzymes are protein catalysts that regulate chemical reactions in living organisms. They accelerate reactions by lowering the activation energy of transition states through interactions with substrates. Enzymes are classified based on the type of reaction they catalyze, such as oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Enzyme kinetics follow the Michaelis-Menten model where the enzyme-substrate complex breaks down into products. The catalytic activity of enzymes is explained by thermodynamic changes in transition states and specific interactions between the enzyme and substrate at its active site.
The document provides information about the respiratory system, including:
- The major contents covered are the introduction, structures of the upper and lower respiratory tract, thoracic wall, and development of the respiratory system.
- The respiratory system's primary roles are to oxygenate cells through gas exchange and remove carbon dioxide, with collaboration from the cardiovascular system.
- The thoracic wall forms the osteocartilaginous thoracic cage, protecting the lungs and heart. It consists of ribs, costal cartilages, thoracic vertebrae, and the sternum.
- Ribs can be typical, atypical, or floating based on their attachments. Typical ribs articulate with the sternum, verte
This document provides information about a medical microbiology course covering respiratory tract infections. The course is part of a pre-clerkship program at Jimma University for medical laboratory sciences students. Topics covered in the respiratory tract infections module include common microbes affecting the respiratory tract, clinical presentations of respiratory infections, diagnostic techniques, and prevention/control methods. The document outlines various upper and lower respiratory tract infections caused by bacteria, viruses, and fungi. [END SUMMARY]
Atelectasis, restrictive and obstructive pulmonary disease.pptxTeshaleTekle1
Atelectasis is the collapse of lung tissue caused by inadequate expansion of air spaces. It is classified into three forms: resorption, compression, and contraction atelectasis. Resorption occurs when an obstruction prevents air from reaching distal airways, causing absorption of existing air and alveolar collapse. Compression results from fluid, blood, or air accumulation in the pleural cavity compressing the lung. Contraction occurs when fibrosis affects lung or pleural expansion. Chronic obstructive pulmonary disease (COPD) includes emphysema and chronic bronchitis. Emphysema is characterized by destruction of alveolar walls leading to enlarged air spaces, while chronic bronchitis involves inflammation of the large airways and
The document summarizes the gross structures and functions of the lower respiratory tract. It describes the trachea as a tubular passageway that branches into the two primary bronchi. The bronchi continue branching into smaller bronchioles that lead to terminal bronchioles and alveoli where gas exchange occurs. It also details the lungs, noting they are highly elastic and each has an apex, lobes divided by fissures, and a root containing bronchial tubes and vessels. The pleurae are membranes that line the thoracic wall and cover the lungs, with a potential space between that contains lubricating fluid.
This document outlines various respiratory diseases including atelectasis, obstructive lung diseases, restrictive lung diseases, and pneumonia. It describes three types of atelectasis - resorption, compression, and contraction atelectasis. Obstructive lung diseases discussed include emphysema, chronic bronchitis, asthma, and bronchiectasis. Emphysema causes abnormal enlargement of airspaces and can be centriacinar, panacinar, or distal acinar. Chronic bronchitis is defined by persistent cough and involves small airway disease and emphysema. Asthma is a chronic inflammatory disorder causing wheezing and reversible airway obstruction. Bronchiectasis results from destruction of bronchial tissue causing permanent dilation
Upper respiratory tract infections are common illnesses that affect the nasal passages, sinuses, pharynx and larynx. The common cold is the most frequent viral illness, often caused by rhinoviruses. Other viral infections like influenza and RSV can cause pharyngitis. Bacterial sinusitis is usually preceded by a viral infection. Acute laryngitis is commonly caused by inhalation of irritants or viral infections. Croup is most often caused by parainfluenza viruses in young children. Nasopharyngeal carcinoma is associated with Epstein-Barr virus and more common in Chinese populations. Laryngeal tumors include non-cancerous lesions like nodules and papillomas as well as
The document discusses the physiology of the renal system, including the structure and function of the kidneys, nephrons, and processes of urine formation such as glomerular filtration, tubular reabsorption and secretion. The kidneys filter blood to remove waste and regulate fluid and electrolyte balance while nephrons are the functional units that filter blood and reabsorb necessary substances through specialized tubule structures like the proximal tubule, loop of Henle, and distal tubule.
The document discusses amino acids and proteins. It begins by listing the learning objectives, which include describing the 20 common amino acids, their structure and classification, as well as the structure and functions of peptides and proteins. It then defines amino acids as the building blocks of proteins, notes that 20 are commonly found in mammalian proteins, and describes their basic structure with an amino group, carboxyl group, hydrogen, and side chain. The document further classifies amino acids based on their chemical, nutritional, and metabolic properties and functions. It also explains how amino acids polymerize to form peptides and proteins, and the levels of structure in proteins from primary to quaternary.
This document discusses lipids, including their structure, classification, and biomedical importance. Lipids are an heterogeneous group of organic compounds that include fats, oils, waxes, and other related substances. They are classified based on factors such as solubility and relationship to fatty acids. The document describes simple lipids like triglycerides, waxes, and sterol esters, as well as complex lipids including phospholipids, glycolipids, and lipoproteins. It also discusses derived lipids such as fatty acids, monoglycerides, and sterols. The biomedical importance of lipids includes roles as energy stores, structural components of cell membranes, thermal insulation, and as carriers of fat-soluble vitamins and essential fatty
Diegestion Absorption of CHO and Hexose sugar metabolism.pdfTeshaleTekle1
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Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...Donc Test
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2. Prosthetic groups, Cofactors and coenzymes
2
Some enzymes require no chemical groups for activity
Many enzymes contain small nonprotein molecules and metal ions that
participate directly in substrate binding or catalysis.
• Prosthetic groups
• Cofactors
• Coenzymes
3. Metal ions as Prosthetic groups or Cofactors
3
Certain mechanisms as to how the metal ions bring about activation:
Direct participation in catalysis
Formation of a metallosubstrate
Formation of a metalloenzyme
Alteration of equilibrium constant
Conformational change in the enzyme
4. Prosthetic groups
4
Prosthetic groups are tightly and stably incorporated into a protein’s structure.
Examples:
• Pyridoxal phosphate
• Flavin mononucleotide (FMN)
• Flavin adenine dinucleotide (FAD)
• Thiamin pyrophosphate
• Biotin
• Metal ions (Co, Cu, Mg, Mn, & Zn)
5. Prosthetic groups
The most common → Metals
~One-third of all enzymes → metalloenzymes
Metals:
Facilitate the binding and orientation of substrates.
Facilitate the formation of covalent bonds with reaction intermediates (co2+ in
coenzyme B12).
Interact with substrates to render them more electrophilic/nucleophilic.
6. Cofactors
6
Cofactors associate reversibly with enzymes or substrates.
Functions similar to those of prosthetic groups.
But bind in a transient,dissociable manner either to the enzyme/a substrate such as ATP.
Most are metal ions
Enzymes that require a metal ion cofactor →metal-activated enzymes
8. Coenzymes
8
Coenzymes serve as Recyclable shuttles:
Substrate shuttles
Group transfer agents:
• Methyl groups (folates)
• Acyl groups (coenzyme A)
• Oligosaccharides
10. • Enzyme concentration
• Substrate concentration
• Temperature
• pH
• Presence of inhibitors/ activators/cofactors
• Electrolyte concentrations
• Specific kinetic properties of the enzyme
• Other factors: intracellular compartmentation/ local microenvironment
Factors affecting enzyme activity
10
11. 1) Substrate concentration:
Rate of enzyme catalyzed reaction increases
with increase in [S] until the maximal
velocity (Vmax) is reached.
NB: afterVmax is reached increasing the [S]
will not have any effect on reaction rate due
to saturation (active sites are occupied by
reactants forming ES).
Factors Affecting rate of the reaction
Effect of substrate concentration on the initial
velocity of an enzyme-catalyzed reaction
11
12. 2)Temperature:
Increase inT increases reaction rate to reach maximum activity due to increased
number of molecules having sufficient energy.
but further increase lowers the rate due to denaturation of the enzyme (loss of
native conformation hence loss of activity)
TheT at which the enzyme is 100% active is termed the optimum
temperature.
Factors affecting….
12
13. 3) pH
The same toT, PH is required for enzyme activity.
but further increase in PH due to denaturation of enzyme brings in sharp decline in
enzyme activity hence reaction rate also decreases.
NB:The pH at which an enzyme is 100% active is termed the optimum PH.
The optimum PH varies for different enzymes.
Some are active at neutral/acidic & Others at neutral PH.
4) Inhibitors also affect enzyme activity.
Factors affecting …
13
14. pH optima for different enzymes (left),and temperature optima for DNA polymerase 1
(Pol1) andTaq (Thermophilus aquaticus) DNA polymerase (right)
14
15. Enzymes (E) + Substrates (S) ⇌ E-S complex ⇌E +P
Enzyme-substrate interactions are generally non-covalent
But chemical bonds are broken and made during an enzyme-catalysed reaction.
Enzyme kinetics
16. 16
Enzyme kinetics………………con’t
The transition state is an unstable “intermediate” during a reaction leading to product
formation.
– Energy is needed to form the transition state.
– Enzymes lower the energy needed to form the transition state.
–comes from binding of substrate to the enzyme
17. Enzyme kinetics………………con’t
Enzymes do not change the overall free energy change of a reaction.
− Do change the energy of activation.
Transition state
17
18. They postulated that the enzyme first combines reversibly with its substrate to form an E-S
complex in a relatively fast reversible step:
The ES complex then breaks down in a slower 2nd step to yield the free E & the reaction
product P.
Because the slower second reaction must limit the rate of the overall reaction, the overall
rate must be proportional to the concentration of the species that reacts in the second step,
that is, ES.
E = enzyme, S = substrate, ES = enzyme-substrate complex, P = product
K1, k-1, k2 & k-2 are rate constants & Km= (k-1+ k2)/k1, where Km =Michaelis
constant
Leonor Michaelis and Maud Menten in 1913
18
19. The Michaelis-Menten Equation:
19
Where,
Vo is the initial velocity
Vmax is the maximal velocity
[S] is the substrate concentration
Km is called the Michaelis Constant
Km is the [S] at (Vmax/2).
related to the affinity of an enzyme for
its substrate.
Michaelis-Menten Enzyme Kinetics
22. Types of enzyme inhibitors
22
Reversible and irreversible inhibitors:
•Most,but not all,drugs are reversible inhibitors.
•Generally speaking,reversible inhibitors bind non-covalently to enzyme.
• Examples of irreversible inhibitors:
•Aspirin (cox 1 and 2 inhibitor)
•Penicillins (inhibit dd-transpeptidase and disrupt peptidoglycan of bacterial cell walls)
•Organophosphate (acetylcholinesterase inhibitors)
•Examples of reversible inhibitors:
•Statins (LDL cholesterol-lowering drugs)
•Peptide-based HIV protease inhibitors
•Influenza virus neuraminidase inhibitors.
23. 23
Irreversible inhibitors of enzymes:
ASPIRIN (acetylsalicylic acid): an irreversible inhibitor of cyclooxygenase enzymes.
Prostaglandin and thromboxane biosynthesis
Involved in numerous processes, including inflammation, body temperature control, pain
sensation, blood clotting.
Aspirin is an anti-inflammatory, analgesic and antipyretic drug and reduces the clotting ability of blood.
(Pg= prostaglandin, tx= thromboxane).
ASPIRIN
24. Aspirin covalently reacts with a serine residue side-chain of cyclooxygenase,
inactivating the enzyme irreversibly.
E= enzyme [cyclo-oxygenase]
SER-OH = serine residue in the enzyme’s active site
CH3
24
25. Irreversible enzyme inhibitors: Penicillins ( and other beta-lactams).
The beta-lactams resemble the chemical structure of D-Ala-D-Ala found in peptides in the
peptidoglycan of the bacterial cell wall.
25
26. 26
Penicillins:
Transpeptidases (penicillin-binding protein, PBP) cross-link the peptidoglycan bacterial
cell wall structure.
cross-linking between D-Ala of one peptide chain to the DAP (diaminopimelic acid) of
another chain.
The enzyme is Irreversibly inactivated by Penicillin and the bacteria rupture.
28. Irreversible enzyme inhibitors: Organophosphate acetylcholinesterase inhibitors:
28
Some insecticides (e.g. malathion) and nerve toxins (e.g. sarin) are organophosphates.
They irreversibly inactivate acetylcholinesterase.
• Prevent the breakdown of the neurotransmitter, acetylcholine.
• Causing many neurotoxic symptoms due to excessive acetylcholine levels.
Symptoms include:
• Paralysis
• Muscle cramps
• Weakness
• Elevated blood pressure
• Seizures
• Ataxia
• Respiratory muscle failure
• Salivation
• Lacrimation
• Sweating
Death is usually due to respiratory muscle paralysis and can occur within minutes of
exposure.
29. *There are three main types of reversible inhibition:
I. Competitive inhibitors
II. Uncompetitive inhibitors
III. Noncompetitive inhibitors
* They interact reversibly with enzyme or (ES)-complex at d/t stages of the reaction process.
29
30. I. Competitive inhibition:
The inhibitor binds to the active site of the enzyme and competes with the substrate for the active site.
The effect of the inhibitor can be overcome by excess substrate, soVmax is not affected. What about Km?
30
31. Example of reversible competitive enzyme inhibitor:
Statins competitively inhibit the rate-limiting enzyme of cholesterol biosynthesis:
HMG-CoA reductase (hydroxymethylglutaryl-CoenzymeA reductase).
They lower low density lipoprotein levels (LDL or “bad cholesterol” in blood in particular.
31
32. FightingAIDS with Inhibitors of HIV ReverseTranscriptase
32
HIV’s reverse transcriptase has a higher affinity for AZT triphosphate than for dTTP, and
binding ofAZT triphosphate to this enzyme competitively inhibits dTTP binding.
WhenAZT is added to the 3’ end of the growing DNA strand, lack of a 3’ hydroxyl means
that the DNA strand is terminated prematurely and viral DNA synthesis stops.
34. Reversible competitive inhibitors:
Influenza neuraminidase inhibitors inhibit competitively the neuraminidase of the virus.
This enzyme is present on the surface of the virus for its entry into human cells.
Neuraminidase inhibitors (e.g. oseltamivir) are used to treat acute influenza virus infections.
34
35. II. Uncompetitive inhibition:The inhibitor can bind only when the substrate is already
bound to the enzyme. Both Km andVmax are decreased.
35
36. III. Noncompetitive Inhibition:
The inhibitor binds to an E to form an EI- complex, and/or to an ES- complex to form an ESI.
The inhibitor binds away from the active site, and the affinity of enzyme for substrate is not affected.
The reaction is slowed down by the inhibitor, and this cannot be overcome by excess substrate.
Vmax is decreased and Km is unchanged.
Noncompetitive inhibition
36
41. 41
Constitutive enzymes are required at all times by a cell and present at some constant
level.
• Housekeeping enzymes
• For example, many enzymes of the central metabolic pathways.
Regulatory enzymes:
Increased or decreased catalytic activity.
42. Regulatory Enzymes
42
Allosteric enzymes are regulated by:
Allosteric effectors/modulator.
Allosteric effector-mediated regulation
Generally small metabolites or cofactors
Other enzymes are regulated by reversible covalent modification.
Some enzymes are stimulated/inhibited when they are bound by separate regulatory
proteins.
Others enzymes are also activated when peptide segments are removed by proteolytic
cleavage
⇛ irreversible
⇛E.g., Zymogens
43. Regulatory Enzymes:Allosteric enzymes
43
Enzymes with several modulators generally have different specific binding sites for each.
The modulators for allosteric enzymes may be inhibitory/stimulatory.
Often the modulator is the substrate itself.
The regulation in which substrate and modulator are identical ⇨homotropic enzymes.
o Active site and regulatory site are the same.
When the modulator is a molecule other than the substrate ⇨ heterotropic enzyme
• E.g., PFK1 ⇦ADP,AMP,ATP & Citrate
44. Regulatory Enzymes:Allosteric enzymes
44
Feedback regulation:
Feedback inhibition: Inhibition of an allosteric enzyme
at the beginning of a metabolic sequence by the end
product of the sequence.
Also known as end-product inhibition
Eg. Regulation of pyruvate dehydrogenase (PDH)
45. Regulatory Enzymes
45
Feedback regulation is not synonymous with feedback inhibition.
For example, dietary cholesterol decreases hepatic synthesis of
cholesterol.
This feedback regulation does not involve feedback inhibition.
Regulation of cholesterol formation balances
synthesis with dietary uptake and energy state
46. Regulatory Enzymes
46
Enzymes modulated by covalent modification
Over 500 different types of covalent modification
Reversible
one or more of its amino acid residues
Like allosteric enzymes, they tend to be multisubunit proteins.
In some cases the regulatory site(s) and the active site are on separate subunits.
49. 49
Examples of mammalian enzymes whose catalytic activity is altered by
covalent phosphorylation-dephosphorylation.
50. Enzymes regulated by proteolytic cleavage
50
Some enzymes are regulated by proteolytic cleavage of an enzyme precursor.
An inactive precursor zymogen is cleaved to form the active enzyme.
Specific cleavage causes conformational changes that expose the enzyme active site.
o E.g., proteases of the stomach and pancrease
o Chymotrypsin & trypsin are initially synthesized as chymotrypsinogen & trypsinogen
51. Activation of zymogens by proteolytic cleavage
51
The three polypeptide chains (A, B, and C) of chymotrypsin
are linked by disulfide bonds
52. Control of Enzyme Synthesis
52
Inducers stimulate the transcription of the gene that encodes regulatory enzymes.
Or transcription factors
Conversely, an excess of a metabolite may act as repressors for repression of
synthesis of regulatory enzymes.
53. Clinical Enzymology in Diagnosis of Disease
Specific enzymes for diagnosis and prognosis of disease.
Deficiencies in the quantity or catalytic activity.
Genetic defects (genetic mutations/infection by viral/bacterial pathogens)
Nutritional deficits
Toxins
Assaying the activity of specific enzymes:
• Blood
• Other tissue fluids
• Cell extracts
53
54. Enzymes as diagnostic biomarkers
1) Functional plasma enzymes (Plasma derived enzymes)
Certain enzymes, proenzymes, and their substrates are present at all times in the
circulation
perform a physiologic function in the blood.
Examples:
• Lipoprotein lipase
• The proenzymes of blood coagulation
The majority are synthesized in and secreted by the liver.
54
55. Enzymes as diagnostic biomarkers
2) Nonfunctional plasma enzymes (Cell derived enzymes)
Plasma also contains numerous other enzymes that perform no known physiologic function in
blood.
Arise from the routine normal destruction of erythrocytes,leukocytes,and other cells.
Tissue damage or necrosis resulting from injury or disease increases their plasma levels
55
56. Enzymes as diagnostic biomarkers
In damaged, infected or inflamed tissue:
Cell membranes become more permeable/destroyed.
The content of the cell cytoplasm → extracellular space → bloodstream
The enzymatic activity can be measured.
Useful in the diagnosis of damage to the heart, liver, muscle, etc.
56
57. Enzymes as diagnostic biomarkers
Unit of serum enzyme activities:
International unit (IU) :
One IU is defined as the activity of the enzyme which transforms one micro mole of
substrate into products per minute per liter of sample under optimal conditions and at
defined temperature .
It is expressed as IU/L
Katal – catalytic unit
One Katal is defined as the number of mole of substrate converted to product
per second per liter of sample.
57
58. Enzymes as diagnostic biomarkers
Enzyme estimations are helpful in the diagnosis of –
Myocardial Infarction
Liver diseases
Muscle diseases
Bone diseases
Cancers
GITract diseases
58
59. Principal Serum Enzymes Used in Clinical Diagnosis
Note:Many of the above enzymes are not specific to the disease list
59
60. Enzyme estimations for diagnosis of Acute Myocaridal Infraction (AMI)
Enzyme assays routinely carried out for the diagnosis of AMI includes;
• Creatine kinase
• Aminotransferases → AST (SGOT) and ALT (SGPT)
• Lactate dehydrogenase
• Cardiac troponin (protein)
60
61. Enzyme estimations for diagnosis of AMI
After a heart attack,a variety of enzymes leak from injured heart cells into the bloodstream.
Blood serum concentrations ALT,AST and CK can be measured by:
• SGPT, SGOT and SCK tests, respectively.
Lactate dehydrogenase also leaks from injured or anaerobic heart muscle.
Provide information about the severity of the damage.
61
62. Creatine kinase
Found in all the muscles of the body.
But much more in skeletal muscle than cardiac muscle.
However, CK activity can be due to one of three isoenzymes
CK1 or CKMM, found mostly in skeletal muscle
CK2 or CKMB, found predominately in cardiac muscle
CK3 or CKBB, found in smooth muscle
Further isoforms of CKMM and CKMB:
Two isoforms of CKMB →MB1 and MB2
Three isoforms of CKMM → MM1, MM2, and MM3
62
63. Lactate dehydrogenase (LDH)
It has at least five different isozymes.
All isozymes contain 4 polypeptide chains.
The M (for muscle) chain and the H (for heart) chain are encoded by two different genes.
63
64. Lipase
Secreted by pancreas and Liver
Hydrolysis of fats
The plasma lipase level may be low in liver disease,Vitamin A deficiency, some
malignancies, and diabetes mellitus.
It may be elevated in acute pancreatitis and pancreatic carcinoma.
64
65. α- Amylase
Dietary starch and glycogen to maltose
Pancreatic juice, saliva, liver fallopian tubes and muscles
Mainly used in the diagnosis of acute pancreatitis.
The plasma amylase level may be low in liver disease
• But increased in high intestinal obstruction,mumps,acute pancreatitis and diabetes.
Trypsin
Secreted by pancreas
Elevated levels in plasma occur during acute pancreatic disease
65
66. Test Abnormality
Serum aminotransferases, for exampleAST,ALT Parenchymal injury
Serum bilirubin Cholestasis
Alkaline phosphatase, γ-glutamyl transferase Biliary epithelial damage and biliary
obstruction (alcohol)
Serum albumin Synthetic function
Prothrombin time (INR) Clotting (dynamic indicator)
Common liver function tests and the abnormalities they detect.
Liver function tests
66
Routine liver function tests (widely performed groups of serum measurements)
67. Liver function tests → Aminotransferases
Aminotransferases (transaminases)
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT)
Their activities are typically 3,000–7,000-fold higher in hepatocytes than in plasma.
Commonly used as a test of hepatocellular damage.
AST is found in liver, heart, skeletal muscle, kidney, brain, and red blood cells.
ALT has a similar distribution, its concentrations are lower in extrahepatic tissues.
67
68. Liver function tests → Aminotransferases
AST exists in both cytosol and mitochondria.
But ALT is in a cytosolic form only.
Reference ranges for AST and ALT are 5–45 IU/L
Increased AST/ALT activity due to liver disease.
An increase in [transaminases] with a relatively smaller increase in other tests indicates
hepatitic liver disease:
I. Infective agents
II. Toxins
III. Autoimmune disorders
68
69. Liver function tests → Aminotransferases
I. Infective agents:
• Hepatitis A/B/C
• Cytomegalovirus (CMV)
• Epstein-barr virus (EBV)
• Others both viral and bacterial
• All produce a significant increase in serum AST/ALT.
ALT is better thanAST for monitoring viral activity in chronic hepatitis B or C.
The higher the relative increase in AST compared to ALP →hepatitis
69
70. Liver function tests → Aminotransferases
II.Toxins
↑AST/ ALT
Alcoholic liver damage is usually chronic and cholestatic (cirrhotic)
• AST/ALT ratio greater than two is suggestive of alcohol misuse.
Many drugs ↑AST/ ALT due to hepatocyte destruction.
• overdosage of paracetamol
Metals can be toxic to the liver & ↑AST/ ALT in the serum.
• An inherited metabolic diseases Cu (Wilson’s disease) & Fe (haemochromatosis)
There is a direct relationship b/n the serum activities of AST and ALT and BMI.
BMI above 30 can increase both by 40–50%.
70
71. Other secondary biochemical liver tests
• Albumin
• Globulins
• Alpha-fetoprotein (AFP)
• Carbohydrate deficient transferrin
• The carbohydrate antigen CA19-9
• Copper/caeruloplasmin
•α1-antitrypsin
71