This document discusses molecular dynamics simulations for in silico drug discovery and design, specifically for HIV/AIDS inhibition research. It covers the physical basis of ligand binding, including noncovalent interactions, binding free energy contributions, and conformational changes upon binding like induced fit and conformational selection. Allostery and linkage between binding sites are also discussed. The goal is to separate and analyze the various enthalpic and entropic contributions to binding through computational methods.
This document discusses ligand interactions and physical and chemical methods used to study protein-ligand interactions. It provides examples of protein-ligand interactions like hemoglobin and myoglobin binding oxygen. It describes how protein-ligand interactions can be quantified using equilibrium expressions and binding constants. Methods to study interactions discussed include yeast two-hybrid assays, affinity tagging, analytical ultracentrifugation, fluorescence resonance energy transfer, and ligand docking.
Proteins interact with other molecules through various types of binding. Reversible binding allows proteins to transport molecules like oxygen, with hemoglobin binding oxygen through a heme group. Binding can be allosteric, affecting other sites; or cooperative, where ligand binding causes conformational changes influencing additional binding. The protein structure complements the ligand, precisely matching its shape and chemistry. Quantitative analyses describe these interactions through equilibrium constants and binding curves.
Introduction
Common terms used
Protein ligand interaction
1)in oxygen binding protein
Heme
Structure of hemoglobin
Ligand binding effected by protein structure
Oxygenation &deoxygenation
Cooperative binding of oxygen
Models for cooperative binding
Hb also transports H+&co2
2)complementary interaction immune system &immunoglobulin
Introduction
Structure of antibodies
Binding of antigen to antibody
Applications
Conclusion
Reference
Proteins are dynamic molecules whose functions almost invariably depend on interactions with other molecules.
A molecule bound reversibly by a protein is called a ligand.
A ligand binds at a site on the protein called the binding site, which is complementary to the ligand in size, shape, charge, and hydrophobic or hydrophilic character.
Protein-ligand interactions are important for enzyme function, receptor actions, and cellular structure formation. Proteins selectively bind to other molecules through spontaneous processes driven by similar forces as protein folding. A protein's function is defined by its interactions with other ligands, which can occur at one or more binding sites. Cooperative effects can influence how additional ligands bind, either positively or negatively. Multivalent interactions between multiple weak binding points on a ligand and protein can also result in high affinity binding. Computational methods can be used to study and model these protein-ligand interactions.
The document summarizes the mechanisms of enzyme catalysis. It discusses how enzymes lower the activation energy of reactions by releasing binding energy when interacting with substrates. This allows enzymes to accelerate reactions by stabilizing transition states. There are three main types of catalytic mechanisms: acid-base catalysis, covalent catalysis, and metal ion catalysis. Acid-base catalysis involves proton transfers. Covalent catalysis forms temporary covalent bonds between enzymes and substrates. Metal ion catalysis uses metal ions like iron and copper to orient and stabilize reactive molecules in enzyme active sites.
Enzyme kinetics can provide information about enzyme activity under different conditions. The Michaelis-Menten approach models enzyme-catalyzed reactions and describes reaction rates with the Michaelis-Menten constant (Km) and maximum reaction rate (Vmax). Enzymes can be inhibited reversibly or irreversibly by inhibitors that reduce reaction rates. Different types of reversible inhibition include competitive, uncompetitive, and mixed inhibition. Temperature, pH, and allosteric effectors can regulate enzymatic activity through various mechanisms.
This document discusses molecular variation in homologous series and isosteric replacements for drug discovery. It defines homologous series as molecules that differ by a methylene group, such as monoalkylated derivatives and cyclopolymethylenic compounds. Biological activity often follows a bell-shaped curve with increasing carbon chain length, peaking at an optimal partition coefficient for membrane crossing. Isosteric replacements involve substituting atoms or groups with others of similar size and electronic properties, allowing modification while maintaining biological activity, as seen with clozapine analogs. The concepts of homologous series and isosteric replacements are important tools in medicinal chemistry for analog design and drug discovery.
This document discusses ligand interactions and physical and chemical methods used to study protein-ligand interactions. It provides examples of protein-ligand interactions like hemoglobin and myoglobin binding oxygen. It describes how protein-ligand interactions can be quantified using equilibrium expressions and binding constants. Methods to study interactions discussed include yeast two-hybrid assays, affinity tagging, analytical ultracentrifugation, fluorescence resonance energy transfer, and ligand docking.
Proteins interact with other molecules through various types of binding. Reversible binding allows proteins to transport molecules like oxygen, with hemoglobin binding oxygen through a heme group. Binding can be allosteric, affecting other sites; or cooperative, where ligand binding causes conformational changes influencing additional binding. The protein structure complements the ligand, precisely matching its shape and chemistry. Quantitative analyses describe these interactions through equilibrium constants and binding curves.
Introduction
Common terms used
Protein ligand interaction
1)in oxygen binding protein
Heme
Structure of hemoglobin
Ligand binding effected by protein structure
Oxygenation &deoxygenation
Cooperative binding of oxygen
Models for cooperative binding
Hb also transports H+&co2
2)complementary interaction immune system &immunoglobulin
Introduction
Structure of antibodies
Binding of antigen to antibody
Applications
Conclusion
Reference
Proteins are dynamic molecules whose functions almost invariably depend on interactions with other molecules.
A molecule bound reversibly by a protein is called a ligand.
A ligand binds at a site on the protein called the binding site, which is complementary to the ligand in size, shape, charge, and hydrophobic or hydrophilic character.
Protein-ligand interactions are important for enzyme function, receptor actions, and cellular structure formation. Proteins selectively bind to other molecules through spontaneous processes driven by similar forces as protein folding. A protein's function is defined by its interactions with other ligands, which can occur at one or more binding sites. Cooperative effects can influence how additional ligands bind, either positively or negatively. Multivalent interactions between multiple weak binding points on a ligand and protein can also result in high affinity binding. Computational methods can be used to study and model these protein-ligand interactions.
The document summarizes the mechanisms of enzyme catalysis. It discusses how enzymes lower the activation energy of reactions by releasing binding energy when interacting with substrates. This allows enzymes to accelerate reactions by stabilizing transition states. There are three main types of catalytic mechanisms: acid-base catalysis, covalent catalysis, and metal ion catalysis. Acid-base catalysis involves proton transfers. Covalent catalysis forms temporary covalent bonds between enzymes and substrates. Metal ion catalysis uses metal ions like iron and copper to orient and stabilize reactive molecules in enzyme active sites.
Enzyme kinetics can provide information about enzyme activity under different conditions. The Michaelis-Menten approach models enzyme-catalyzed reactions and describes reaction rates with the Michaelis-Menten constant (Km) and maximum reaction rate (Vmax). Enzymes can be inhibited reversibly or irreversibly by inhibitors that reduce reaction rates. Different types of reversible inhibition include competitive, uncompetitive, and mixed inhibition. Temperature, pH, and allosteric effectors can regulate enzymatic activity through various mechanisms.
This document discusses molecular variation in homologous series and isosteric replacements for drug discovery. It defines homologous series as molecules that differ by a methylene group, such as monoalkylated derivatives and cyclopolymethylenic compounds. Biological activity often follows a bell-shaped curve with increasing carbon chain length, peaking at an optimal partition coefficient for membrane crossing. Isosteric replacements involve substituting atoms or groups with others of similar size and electronic properties, allowing modification while maintaining biological activity, as seen with clozapine analogs. The concepts of homologous series and isosteric replacements are important tools in medicinal chemistry for analog design and drug discovery.
This document discusses enzyme kinetics and inhibition. It describes how enzymes exert kinetic control over metabolic pathways and reactions. It aims to determine the maximum velocity, substrate affinity, and inhibitor affinity of enzymes. This can provide information about metabolic pathway flow, substrate utilization, and how to manipulate metabolic events. The document also discusses Michaelis-Menten kinetics, Lineweaver-Burk plots, competitive and non-competitive inhibition, and how inhibitors can be used to study enzyme mechanism and regulation.
The document discusses the four levels of protein structure: primary, secondary, tertiary, and quaternary. It provides examples of common secondary structures like alpha helices and beta sheets. Tertiary structure describes the 3D arrangement of all atoms in the protein. Quaternary structure refers to the association of multiple polypeptide chains. The document outlines various experimental techniques used to determine protein structure like X-ray crystallography and NMR.
This document provides an overview of molecular variation in homologous series and isosteric replacements for medicinal chemistry. It discusses different types of molecular variations such as variations based on homologous series with different biological response curves. It also discusses isosteric replacements, including the history and development of isosterism concepts. Current isosteric and bioisosteric modifications are presented. The document also discusses molecular variations based on ring transformations, homodimer and heterodimer ligands using the twin drug approach, and molecular variations in medicinal chemistry applications.
Enzyme catalysis, effect of organic solventKAUSHAL SAHU
INTRODUCTION
Enzyme catalysis
Mechanisms of catalysis
Organic solvent
Classes of Organic Solvent
Biocatalysis in organic solvents
Enzyme Reactions in Organic solvents
Effect of the organic solvent in enzyme catalysis
Conclusion
References
Analog design is usually defined as the modification of a drug molecule or of any bioactive compound in order to prepare a new molecule showing chemical and biological similarity with the original model compound
This document discusses catalysts and enzyme catalysis. It provides information on:
1) How catalysts work by lowering the activation energy of reactions, either by stabilizing transition states, converting reactants to more reactive forms, or changing reaction mechanisms.
2) Examples of different types of catalysts including acids, bases, and metal ions. Acids and bases can be specific or general depending on when proton transfer occurs.
3) How enzymes are highly effective biological catalysts due to positioning of reactants, inclusion of catalytic groups, and stabilization of transition states.
4) Features of two example enzymes, carboxypeptidase A and lysozyme, including their catalytic mechanisms and substrate specificity.
The content includes the general introduction of enzymes their basic classification. Enzyme kinetics is described with a short view of Michaelis menten constants. Factors affecting the kinetics of enzymes are also discussed. Principles of enzyme inhibition are discussed with a few examples.
The contents is prepared by the help of books, internet sources, as well as other presentations. I am thankful to all of you.
Globular proteins serve many important functions in the body:
- They transport molecules like oxygen (hemoglobin) and glucose.
- They store ions and molecules for later use (myoglobin, ferritin).
- They catalyze biochemical reactions as enzymes.
Proteins interact with other molecules through their binding sites. The affinity between a ligand and protein binding site is described by the dissociation constant (Kd), with a lower Kd indicating tighter binding. Both the lock-and-key and induced fit models explain how proteins achieve specific binding of ligands.
This document discusses key concepts in medicinal chemistry including receptor interactions, drug potency and efficacy, and the stereochemical effects of drug enantiomers. Specifically, it defines receptor down-regulation as a decrease in receptor numbers induced by an agonist, and receptor up-regulation as the opposite, an agonist-induced increase in receptor numbers. It also explains that drug potency depends on both affinity, the ability of a drug to bind a receptor, and efficacy, the intensity of response produced by an agonist occupying receptors. Finally, it notes some stereoselective differences in the absorption, distribution, metabolism and excretion of drug enantiomers.
This document discusses methods for analyzing complexation and protein binding. It describes four main methods for determining the stoichiometric ratio and stability constant of complexes: continuous variation, pH titration, distribution, and solubility methods. It provides examples of how each method works and the types of calculations used. It also discusses kinetics of protein binding, describing protein-drug interactions and equations used to determine association constants and binding sites.
This document discusses complexation and protein binding. It defines complex compounds as molecules where some bonds cannot be described by classical valence theory. Complexation is the association of two molecules to form a non-covalently bonded entity with a stoichiometry. Ligands interact with central metal ions or atoms via coordinate bonds to form metal complexes. Protein binding is the formation of drug-protein complexes. Factors affecting protein binding include the drug's physicochemical properties, protein concentration and binding sites, drug interactions, and patient characteristics like age and disease state. Kinetics of protein binding influence drug absorption, distribution, metabolism, and elimination.
1. Geometrical isomerism, such as cis-trans isomerism, can create different pharmacological effects because the orientation of atoms determines if a drug can properly bind to its target, like how only the cis isomer of cisplatin can bind to DNA in cancer cells.
2. Chirality is important in drug action because two enantiomers of a drug act differently in the body, with one potentially causing harmful side effects like thalidomide while the other has the desired effect.
3. The beta-lactam ring in penicillin is important because its strained structure makes it highly reactive and able to covalently bond to bacterial cell wall enzymes, blocking their action.
This document discusses enzyme kinetics and catalytic mechanisms. It provides details on:
1. The catalytic triad of serine proteases (Ser195, His57, Asp102) and how inhibitors like DIPF can label the active site serine, disabling the enzyme.
2. The kinetic steps of enzyme-catalyzed reactions, including substrate binding, formation of a tetrahedral intermediate, and release of products.
3. How transition state theory is used to explain the kinetic barrier for reactions, and how enzymes lower this activation energy to greatly increase reaction rates.
4. How reaction rates depend on parameters like temperature, activation energy, and catalysts through equations derived from Arrhenius kinetics
Role of chirality in stereoselective and specific theraputic agentKaranvir Rajput
This document discusses the role of chirality in selective therapeutic agents. It begins by defining isomerism and the different types of isomers including constitutional, stereoisomers, optical isomers, enantiomers, and diastereomers. It then discusses the discovery of optical activity and chirality. The key points are that humans are chiral beings and the enantiomers of chiral drugs may have different biological effects. Several examples are given to illustrate how the biological activity of enantiomers can differ, including some being more active, having opposing effects, or one causing toxicity. The importance of understanding chirality in drug development and safety is emphasized.
Stereochemistry refers to the three-dimensional orientation of atoms in space. The physiological properties of a drug are greatly influenced by its stereochemistry. Even optical isomers of a drug, which have the same molecular formula and connectivity but differ in their three-dimensional atomic arrangements, can have different physiological effects. There are two main types of isomerism: optical isomerism, which involves chiral centers, and geometrical isomerism, which involves differences in spatial arrangements around a double bond. The separation of isomers in a mixture is technically difficult but important as isomers can have different biological activities.
This document discusses stereoisomers in pharmacology. It begins with an introduction to stereochemistry and the three types of isomers - constitutional, configurational, and conformational. It then discusses the history of isomerism, chirality, enantiomers, and nomenclature systems. The document outlines important differences between single enantiomers and racemic mixtures in terms of pharmacokinetic and pharmacodynamic properties. It provides several examples to illustrate these differences. Finally, the document concludes that increasing availability of single-enantiomer drugs can provide safer, better tolerated, and more efficacious treatments compared to racemic mixtures.
Complexation and Protein Binding [Part-1](Introduction and Classification an...Ms. Pooja Bhandare
Complexation: Classification of complexation:
Metal ion or co-ordination complexes :
Inorganic type Organic molecular complexes :
Quinhydrone type
Picric acid type
Caffeine and other drug complexes
Polymer type
Inclusion or occlusion compound
Channel lattice type
Layer type
Monomolecular type
Macromolecular type
Chelates
Olefin type
Aromatic type
Pi (п) complexes
Sigma (б) complexes
Sandwich complexes
Stereochemistry in drug design discusses the importance of stereochemistry in drug development. It covers different types of stereoisomers like enantiomers and diastereoisomers and geometric isomers. It also discusses the thalidomide disaster and Easson-Stedman hypothesis that differences in biological activity between enantiomers result from selective reactivity of one enantiomer with receptors requiring a three-point fit. Finally, it provides examples of drugs with multiple chiral centers, geometric isomerism, conformational isomers, and acetylcholine.
Fuctional group determination of drugs in biological activity.vishnu chinnamsetti
The document discusses the role of functional groups in determining biological activity. It defines functional groups as atoms within drug molecules that confer specific chemical and physical properties. The key points are:
1) Functional groups determine properties like ionization, solubility, reactivity, stability, and metabolism. They impact drug shelf life, action duration, and susceptibility to metabolism.
2) There are several types of functional groups including acidic, basic, hydrophilic, intermediate polarity, and lipophilic groups. These groups impact properties like water solubility, lipid solubility, and ability to cross cell membranes.
3) The presence of particular functional groups is important for a drug's intended biological activity and receptor interactions. Understanding functional
Chapter 05 an overview of organic reactions.Wong Hsiung
This document provides an overview of organic reactions, including the different types of organic reactions and how reaction mechanisms are used to describe the steps involved in organic reactions. It discusses several key aspects of organic reactions, including: 1) the common types of organic reactions such as addition, elimination, substitution, and rearrangement reactions, 2) how reaction mechanisms are used to describe the individual steps that occur in organic reactions, from reactants to products, and 3) the different types of steps that can be involved in reaction mechanisms, including the formation and breaking of covalent bonds. It also provides examples of reaction mechanisms, such as the addition of HBr to ethylene.
The document discusses a study that measured the electrical conductivity of solutions of sodium polystyrenesulphonate in mixed solvent systems of 2-ethoxyethanol and water at varying concentrations, temperatures, and solvent compositions. The results showed that equivalent conductivity increased slightly with decreasing polymer concentration. Equivalent conductivity also increased with increasing temperature and relative permittivity of the solvent system. However, the experimentally determined conductivities did not fully match what was predicted by Manning's counterion condensation theory. Reasons for this discrepancy are discussed.
Unit –II : Chemical Dynamics Potential energy surfaces, Kinetic isotopic effe...RamiahValliappan2
Potential energy surfaces, Kinetic isotopic effects - Dynamics of unimolecular reactions – Lindemann-Hinshelwood – Rice Ramsperger Kassel (RRK) theory and Rice Ramsperger Kassel – Marcus (RRKM) theory. Study of fast reactions by laser, relaxation, flash Photolysis and nuclear magnetic resonance methods. LFERs -Hammett equation, Taft equation, separation of polar, resonance and steric effects.
This document discusses enzyme kinetics and inhibition. It describes how enzymes exert kinetic control over metabolic pathways and reactions. It aims to determine the maximum velocity, substrate affinity, and inhibitor affinity of enzymes. This can provide information about metabolic pathway flow, substrate utilization, and how to manipulate metabolic events. The document also discusses Michaelis-Menten kinetics, Lineweaver-Burk plots, competitive and non-competitive inhibition, and how inhibitors can be used to study enzyme mechanism and regulation.
The document discusses the four levels of protein structure: primary, secondary, tertiary, and quaternary. It provides examples of common secondary structures like alpha helices and beta sheets. Tertiary structure describes the 3D arrangement of all atoms in the protein. Quaternary structure refers to the association of multiple polypeptide chains. The document outlines various experimental techniques used to determine protein structure like X-ray crystallography and NMR.
This document provides an overview of molecular variation in homologous series and isosteric replacements for medicinal chemistry. It discusses different types of molecular variations such as variations based on homologous series with different biological response curves. It also discusses isosteric replacements, including the history and development of isosterism concepts. Current isosteric and bioisosteric modifications are presented. The document also discusses molecular variations based on ring transformations, homodimer and heterodimer ligands using the twin drug approach, and molecular variations in medicinal chemistry applications.
Enzyme catalysis, effect of organic solventKAUSHAL SAHU
INTRODUCTION
Enzyme catalysis
Mechanisms of catalysis
Organic solvent
Classes of Organic Solvent
Biocatalysis in organic solvents
Enzyme Reactions in Organic solvents
Effect of the organic solvent in enzyme catalysis
Conclusion
References
Analog design is usually defined as the modification of a drug molecule or of any bioactive compound in order to prepare a new molecule showing chemical and biological similarity with the original model compound
This document discusses catalysts and enzyme catalysis. It provides information on:
1) How catalysts work by lowering the activation energy of reactions, either by stabilizing transition states, converting reactants to more reactive forms, or changing reaction mechanisms.
2) Examples of different types of catalysts including acids, bases, and metal ions. Acids and bases can be specific or general depending on when proton transfer occurs.
3) How enzymes are highly effective biological catalysts due to positioning of reactants, inclusion of catalytic groups, and stabilization of transition states.
4) Features of two example enzymes, carboxypeptidase A and lysozyme, including their catalytic mechanisms and substrate specificity.
The content includes the general introduction of enzymes their basic classification. Enzyme kinetics is described with a short view of Michaelis menten constants. Factors affecting the kinetics of enzymes are also discussed. Principles of enzyme inhibition are discussed with a few examples.
The contents is prepared by the help of books, internet sources, as well as other presentations. I am thankful to all of you.
Globular proteins serve many important functions in the body:
- They transport molecules like oxygen (hemoglobin) and glucose.
- They store ions and molecules for later use (myoglobin, ferritin).
- They catalyze biochemical reactions as enzymes.
Proteins interact with other molecules through their binding sites. The affinity between a ligand and protein binding site is described by the dissociation constant (Kd), with a lower Kd indicating tighter binding. Both the lock-and-key and induced fit models explain how proteins achieve specific binding of ligands.
This document discusses key concepts in medicinal chemistry including receptor interactions, drug potency and efficacy, and the stereochemical effects of drug enantiomers. Specifically, it defines receptor down-regulation as a decrease in receptor numbers induced by an agonist, and receptor up-regulation as the opposite, an agonist-induced increase in receptor numbers. It also explains that drug potency depends on both affinity, the ability of a drug to bind a receptor, and efficacy, the intensity of response produced by an agonist occupying receptors. Finally, it notes some stereoselective differences in the absorption, distribution, metabolism and excretion of drug enantiomers.
This document discusses methods for analyzing complexation and protein binding. It describes four main methods for determining the stoichiometric ratio and stability constant of complexes: continuous variation, pH titration, distribution, and solubility methods. It provides examples of how each method works and the types of calculations used. It also discusses kinetics of protein binding, describing protein-drug interactions and equations used to determine association constants and binding sites.
This document discusses complexation and protein binding. It defines complex compounds as molecules where some bonds cannot be described by classical valence theory. Complexation is the association of two molecules to form a non-covalently bonded entity with a stoichiometry. Ligands interact with central metal ions or atoms via coordinate bonds to form metal complexes. Protein binding is the formation of drug-protein complexes. Factors affecting protein binding include the drug's physicochemical properties, protein concentration and binding sites, drug interactions, and patient characteristics like age and disease state. Kinetics of protein binding influence drug absorption, distribution, metabolism, and elimination.
1. Geometrical isomerism, such as cis-trans isomerism, can create different pharmacological effects because the orientation of atoms determines if a drug can properly bind to its target, like how only the cis isomer of cisplatin can bind to DNA in cancer cells.
2. Chirality is important in drug action because two enantiomers of a drug act differently in the body, with one potentially causing harmful side effects like thalidomide while the other has the desired effect.
3. The beta-lactam ring in penicillin is important because its strained structure makes it highly reactive and able to covalently bond to bacterial cell wall enzymes, blocking their action.
This document discusses enzyme kinetics and catalytic mechanisms. It provides details on:
1. The catalytic triad of serine proteases (Ser195, His57, Asp102) and how inhibitors like DIPF can label the active site serine, disabling the enzyme.
2. The kinetic steps of enzyme-catalyzed reactions, including substrate binding, formation of a tetrahedral intermediate, and release of products.
3. How transition state theory is used to explain the kinetic barrier for reactions, and how enzymes lower this activation energy to greatly increase reaction rates.
4. How reaction rates depend on parameters like temperature, activation energy, and catalysts through equations derived from Arrhenius kinetics
Role of chirality in stereoselective and specific theraputic agentKaranvir Rajput
This document discusses the role of chirality in selective therapeutic agents. It begins by defining isomerism and the different types of isomers including constitutional, stereoisomers, optical isomers, enantiomers, and diastereomers. It then discusses the discovery of optical activity and chirality. The key points are that humans are chiral beings and the enantiomers of chiral drugs may have different biological effects. Several examples are given to illustrate how the biological activity of enantiomers can differ, including some being more active, having opposing effects, or one causing toxicity. The importance of understanding chirality in drug development and safety is emphasized.
Stereochemistry refers to the three-dimensional orientation of atoms in space. The physiological properties of a drug are greatly influenced by its stereochemistry. Even optical isomers of a drug, which have the same molecular formula and connectivity but differ in their three-dimensional atomic arrangements, can have different physiological effects. There are two main types of isomerism: optical isomerism, which involves chiral centers, and geometrical isomerism, which involves differences in spatial arrangements around a double bond. The separation of isomers in a mixture is technically difficult but important as isomers can have different biological activities.
This document discusses stereoisomers in pharmacology. It begins with an introduction to stereochemistry and the three types of isomers - constitutional, configurational, and conformational. It then discusses the history of isomerism, chirality, enantiomers, and nomenclature systems. The document outlines important differences between single enantiomers and racemic mixtures in terms of pharmacokinetic and pharmacodynamic properties. It provides several examples to illustrate these differences. Finally, the document concludes that increasing availability of single-enantiomer drugs can provide safer, better tolerated, and more efficacious treatments compared to racemic mixtures.
Complexation and Protein Binding [Part-1](Introduction and Classification an...Ms. Pooja Bhandare
Complexation: Classification of complexation:
Metal ion or co-ordination complexes :
Inorganic type Organic molecular complexes :
Quinhydrone type
Picric acid type
Caffeine and other drug complexes
Polymer type
Inclusion or occlusion compound
Channel lattice type
Layer type
Monomolecular type
Macromolecular type
Chelates
Olefin type
Aromatic type
Pi (п) complexes
Sigma (б) complexes
Sandwich complexes
Stereochemistry in drug design discusses the importance of stereochemistry in drug development. It covers different types of stereoisomers like enantiomers and diastereoisomers and geometric isomers. It also discusses the thalidomide disaster and Easson-Stedman hypothesis that differences in biological activity between enantiomers result from selective reactivity of one enantiomer with receptors requiring a three-point fit. Finally, it provides examples of drugs with multiple chiral centers, geometric isomerism, conformational isomers, and acetylcholine.
Fuctional group determination of drugs in biological activity.vishnu chinnamsetti
The document discusses the role of functional groups in determining biological activity. It defines functional groups as atoms within drug molecules that confer specific chemical and physical properties. The key points are:
1) Functional groups determine properties like ionization, solubility, reactivity, stability, and metabolism. They impact drug shelf life, action duration, and susceptibility to metabolism.
2) There are several types of functional groups including acidic, basic, hydrophilic, intermediate polarity, and lipophilic groups. These groups impact properties like water solubility, lipid solubility, and ability to cross cell membranes.
3) The presence of particular functional groups is important for a drug's intended biological activity and receptor interactions. Understanding functional
Chapter 05 an overview of organic reactions.Wong Hsiung
This document provides an overview of organic reactions, including the different types of organic reactions and how reaction mechanisms are used to describe the steps involved in organic reactions. It discusses several key aspects of organic reactions, including: 1) the common types of organic reactions such as addition, elimination, substitution, and rearrangement reactions, 2) how reaction mechanisms are used to describe the individual steps that occur in organic reactions, from reactants to products, and 3) the different types of steps that can be involved in reaction mechanisms, including the formation and breaking of covalent bonds. It also provides examples of reaction mechanisms, such as the addition of HBr to ethylene.
The document discusses a study that measured the electrical conductivity of solutions of sodium polystyrenesulphonate in mixed solvent systems of 2-ethoxyethanol and water at varying concentrations, temperatures, and solvent compositions. The results showed that equivalent conductivity increased slightly with decreasing polymer concentration. Equivalent conductivity also increased with increasing temperature and relative permittivity of the solvent system. However, the experimentally determined conductivities did not fully match what was predicted by Manning's counterion condensation theory. Reasons for this discrepancy are discussed.
Unit –II : Chemical Dynamics Potential energy surfaces, Kinetic isotopic effe...RamiahValliappan2
Potential energy surfaces, Kinetic isotopic effects - Dynamics of unimolecular reactions – Lindemann-Hinshelwood – Rice Ramsperger Kassel (RRK) theory and Rice Ramsperger Kassel – Marcus (RRKM) theory. Study of fast reactions by laser, relaxation, flash Photolysis and nuclear magnetic resonance methods. LFERs -Hammett equation, Taft equation, separation of polar, resonance and steric effects.
This is a PRESENTATION just to help students to easily understand one of the method of drug designing i.e. QSAR.. this is a combination of many slides and books..this is not my personal.
Bioenergetics is the study of energy relationships and conversions in living systems. All biological transformations obey the laws of thermodynamics. A system exchanges either matter or energy or both with its surroundings and includes reactants, products, and the immediate environment. Closed systems exchange energy but not matter, while open systems exchange both. Spontaneous reactions are exergonic with a negative change in free energy, while non-spontaneous reactions are endergonic with a positive change in free energy. Cellular functions depend on endergonic reactions being coupled to exergonic reactions to make the overall process exergonic. Drug-receptor binding affinity is determined by the free energy change and can be calculated from contributions
This document provides an overview of biochemical thermodynamics and key concepts including enthalpy, entropy, free energy, and their relationships. It discusses how biochemical reactions are classified based on their standard free energy changes as either exergonic (spontaneous) or endergonic (non-spontaneous). The role of ATP as the main energy currency in cells is explained. Redox potentials of electron transport chain components are provided. Important energy-rich compounds in biological systems like ATP, phosphocreatine, and acetyl CoA are introduced along with their structures and significance.
Solvation can be defined as any stabilizing interaction of a solute (or solute moiety) and the solvent. These interactions can be weak, purely electrostatic, as is the case with non-polar solutes and solvents, or more significant, involving the interactions between dipole moments or between dipoles and formal charges.
Contributed by: Anton S. Klimenko (Undergraduate), Department of Chemistry, The University of Utah, 2016
1. The document discusses mechanisms of substitution reactions in coordination compounds, including dissociative, associative, and interchange mechanisms. It provides details on the steps and intermediates involved in each.
2. Factors that affect the rates of substitution reactions are also examined, such as temperature, pressure, ionic strength, and solvent. The relationships between these factors and reaction rates are defined.
3. Dissociative and associative mechanisms are described for the replacement of coordinated water by other ligands in octahedral metal complexes. Evidence suggests dissociative (SN1-like) processes are often involved when the rate depends only on the metal complex concentration.
The document discusses the Linear Free Energy Relationship known as the Hammett Equation. It describes how the Hammett Equation can be used to investigate organic reaction mechanisms by studying the effects of substituents on reaction rates. The key aspects are:
1) The Hammett Equation relates the logarithm of reaction rates or equilibrium constants to substituent constants (σ) using the reaction constant (ρ).
2) σ values describe electronic properties of substituents, with electron-withdrawing groups having positive σ and electron-donating groups having negative σ.
3) ρ indicates how sensitive a reaction is to substituents, relating the electronic demand of the reaction transition state. Its sign and magnitude provide insight into
1. Enzymes are biological catalysts that speed up chemical reactions without being consumed in the process. They do this by lowering the activation energy of reactions.
2. Most enzymes are proteins that contain an active site where substrates bind and reactions occur. Enzymes exhibit high specificity and can accelerate reactions by factors of millions.
3. The Michaelis-Menten model describes enzyme kinetics, showing that reaction velocity is determined by the concentration of the enzyme-substrate complex and reaches a maximum velocity (Vmax) as substrate concentration increases. This model is important for understanding how enzymes function.
Organic reactions occur between organic molecules containing carbon and hydrogen. There are several types of organic reactions including addition, elimination, substitution, and rearrangement. Organic reactions are also classified by reaction type such as acid-base reactions and redox reactions. Reactions proceed through the formation of unstable intermediates like carbocations, carbanions, free radicals, and radical ions before products form. Factors like energetics, electronic effects, steric effects, stereoelectronic effects, solvent effects influence organic reactions. Reactions require activation energy to reach a transition state before products form.
1. Organic reaction mechanisms involve the reaction of a substrate with a reagent, forming intermediates and ultimately products.
2. Bond cleavage can occur through either a heterolytic or homolytic process. Heterolytic cleavage leads to the formation of ions while homolytic cleavage leads to free radicals.
3. Electrophiles are electron seeking species that attack nucleophilic centers, while nucleophiles are electron pairing species that attack electrophilic centers. Common electrophiles include carbocations and carbonyl groups, while common nucleophiles include carbanions.
1. The document discusses drug-receptor interactions and how drugs target macromolecules like proteins, lipids, carbohydrates, and nucleic acids.
2. Drug-receptor binding can occur through different types of interactions including covalent bonds, ionic/electrostatic interactions, hydrogen bonding, charge-transfer bonds, and van der Waals forces. The functional groups on drugs use their electronic and shape properties to facilitate binding.
3. Receptors are membrane-bound proteins that selectively bind to ligands, resulting in a physiological response. The stability of the drug-receptor complex depends on the drug's affinity for the receptor. Affinity, efficacy, and potency determine a drug's biological
This document discusses electric polarizability dispersion of alumina particles with adsorbed carboxymethyl cellulose. There is debate in the literature about whether condensed counterions along polymer chains are mobile or immobile when an electric field is applied. This experimental study uses electric light scattering to investigate an aqueous suspension of alumina particles with adsorbed carboxymethyl cellulose at different polyelectrolyte concentrations. The results indicate no additional polarizability component from condensed counterions, suggesting they are immobile in a sinusoidal electric field of moderate intensity from 10 Hz to 1 MHz.
Organic Reaction Mechanism : This topic is very-very important for CSIR-NET, GATE, IIT-JAM and other Competitive exams for Chemistry and Chemical Sciences.
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Chapter 1 the physical basis of ligand binding
1. IN SILICO DRUG
DISCOVERY AND DESIGN
NUMERICAL COMPUTATION OF MOLECULAR DYNAMICS IN
HIV/AIDS INHIBITION RESEARCH
BENEDIKTUS MA’DIKA
IZZADIEN IBRAHIM
RIFQI ALVIANSYAH
3. 1.1 INTRODUCTION
• Noncovalent binding :enzymes/substrates, ligands/receptors, or proteins/nucleic acids
• Specificity is needed to preserve the correctness of the biochemical pathways and the
integrity of the information
• Binding affinity and specificity are often provided by noncovalent interactions through
hydrogen bonds, salt bridges, tight packing of complementary molecular surfaces, and
hydrophobic forces mediated by solvent, although longer-range electrostatic interactions
also play a role, particularly in the formation of encounter complexes
• binding free energy t are specifically associated with the solute degrees of freedom: external
rotations/translations and internal vibrations.
• To isolate some of the free energy contributions more clearly, we introduce a multistep
binding path, where the ligand is first uncharged, then moved into the binding site, and
then recharged. This allows us to separate (mostly) the discussion of electrostatic and
hydrophobic effects
4. 1.1 INTRODUCTION
• drug-like molecules can have complex energy surfaces, with polar, nonpolar, and
polarizable groups, hard and soft degrees of freedom, multiple protonation states,
possibly co-bound ions, all of which can reorganize on binding
• They must recognize dynamic, fluctuating, macromolecular targets,displace water
molecules, and compete with a host of other molecules
• In reality, the cell is crowded, stochastic, chemically open, and out of equilibrium.
This is the most basic and important framework with which to start an analysis of
biological ligand binding
• RNA and DNA have some specific properties as receptors, including a high density
of ionic phosphate groups, a corresponding ion cloud, their particular tertiary
organization, and the high flexibility of some weakly structured RNAs
5. 1.2 DEFINING THE BOUND STATE
• conformations where the ligand is within a well-defined binding pocket would be labeled “bound.”
deep energy well, so that ligand conformations near the boundary of the pocket will have high
energies and low statistical weights. Thus, it does not affects binding constant
when the binding of two similar ligands to a receptor is compared, there will be some cancellation
of the boundary region contributions of each ligand.
Even if two definitions of the binding site volume differ by a factor of 2, the two definitions of the
binding free energy would typically differ by kT log 2, just 0.4 kcal/mol at room temperature .Such
a change is not too important for a nanomolar binder at micromolar doses (a few grams in the
bloodstream).
• Experiments measure a physical signal, such as heat release or optical energy absorption, and we
should consider which conformations contribute to the experimental signal and use them as the
basis for comparison.
• The most direct approach is to compute the physical signal directly from a simulation including
include NMR chemical shifts, pKa shifts for protonation of a reporter group, fluorescence spectra,
shifts in vibrational infrared bands, and so on.
• the most common approach in free energy simulations is to compute binding free energy for one or
a few specific sites
6. 1.3 CHEMICAL POTENTIALS AND MASS
ACTION
• Chemical potential governs binding equilibria in solution
• If the solution is dilute
• For the binding free energy, if we choose [R]° = [L]° = [RL]° = C° for simplicity
concentrations are held
fixed through some kind of
constraints
constraints are removed
the only assumptions in this derivation are infinite dilution,
nonionic solutes, and the validity of classical statistical
mechanics. The derivation holds if the solute is not dilute but
intersolute interactions are absent, as in the usual 1 M “ideal-
dilute” standard state
Biochemical applications
routinely involve ionic
ligands and/or receptors,
so it is essential to generalize
these equation for this case
7. 1.3 CHEMICAL POTENTIALS AND MASS
ACTION
• If we consider a neutral pair of solutes X, Y that form a monovalent 1:1 salt, with [X] =
[Y]
• infinite dilution, γX has a very simple concentration dependence
• As the ion concentrations approach 0, the activity coefficients approach 1, so the law of
mass action is still valid.
8. 1.4 FREE ENERGY CONTRIBUTIONS
ASSOCIATED WITH SOLUTE MOTIONS
• loss of solute translation entropy leads to a distinct, concentration-dependent term in the binding
free energy.
• the solute partition function and chemical potential contain several contributions associated with
its overall translation, which are all independent of the solvent and separable from the other
contributions
• rotation also leads to distinct contributions that are largely independent of the solvent (in the
dilute limit).
• intrasolute motions:
vibrational terms associated with oscillations within an energy basin
conformational terms associated with degrees of freedom that have several distinct energy basins
• Integrating Out the Solvent: The PMF
Potential energy function U as a function of the solute and solvent coordinate vectors;X and Y:
U(X,Y) = Uu(X) + Uuv(X,Y) + Uv(Y)
The configurational partition function for the whole system:
9. 1.4 FREE ENERGY CONTRIBUTIONS
ASSOCIATED WITH SOLUTE MOTIONS
PMF or W(X) can be interpreted by noting that δW = W − Uu is the free energy to transfer the solute from
vacuum into solvent when it is held fixed in the conformation X
• Solute Translations and Rotations
let QX trans=(qXtrans)^nx /n X/ ! be the contribution to the partition function that arises from overall
translations of the nX solute molecules, including the nX! factor for their possible permutations.
Rotational kinetic energy and entropy are also largely or entirely separable and independent of the solvent
10. • the rotational contribution to the solute partition function and chemical potential
• Solute Vibrations and Conformational Changes
quasiharmonic model, We compute the atomic fluctuations from a molecular dynamics simulation, which
can use a realistic energy function and solvent environment.
we compute the atomic displacement covariance matrix C, where Cij = xixj •; xi represents the
displacement of the atomic coordinate xi from its mean position, and the brackets represent a time average.
We determine the matrix H of force constants that would lead to the observed covariances, if the solute
dynamics were harmonic, from the relation ; H = kT C^−1.
Finally, we diagonalize a mass weighted version of H to obtain the corresponding “quasiharmonic”
vibrational modes and their enthalpy and entropy
11. • single vibrational mode, of frequency v and
treated quantum mechanically, contributes to
the partition function and chemical potential
according to
• To express the contribution of multiple energy
wells and conformations formally, it is helpful
to integrate out the solvent degrees of
freedom, as above (Equation 1.9), and write
the free energy or the entropy as an integral
over the remaining, 3N solute coordinates X =
(r1, …, rN):
12. 1.8 ENTHALPY, ENTROPY, AND THEIR
COMPENSATION
• When optimizing a ligand, a rule of thumb is that “binding opposes motion”: we may
introduce groups to form new interactions, only to find that the gain in binding enthalpy is
erased because the new complex is tighter and has a lower entropy.
• For biochemical binding reactions, the measured enthalpy and entropy are usually larger
than the free energy, which implies a certain level of compensation.
• The simplest idea is that a deeper energy well, for an RL complex, will also be narrower,
leading to reduced vibrational entropy
13. 1.9 CONFORMATIONAL SELECTION AND
INDUCED FIT
• Ligand-induced proton binding and release are the main source of
the pH dependence of the binding affinity
• With induced fit (IF), the receptor rearranges after the ligand has
become partly or fully bound
• With conformation selection(CS),the rearrangements occur before
binding, and the ligand simply selects a conformation that
preexisted—albeit with a low occupancy, and pins it in place
• In statistical physics, the concept is distinctly older: the
“fluctuation- dissipation” theorem shows that the response of a
system to a perturbation (such as ligand binding) can be
understood from its fluctuations in the absence of the
perturbation .This is the basis of linear response theory, which is
widely used in biochemistry, for example, for protein electrostatics
and ligand binding.
• In general, the binding reaction is more complex, with a series of
conformational rearrangements occurring, some before and some
after binding
14. 1.10 ALLOSTERY AND LINKAGE
• An essential requirement in the cell is to combine and process information from multiple
channels, building up networks for signaling, energy transduction, or metabolism.
• Crosstalk between two ligands that bind the same biomolecule is referred to either as
linkage or allostery.
• The most common mechanism for allostery is for one ligand to select or induce a
conformational change that affects a second, distant binding site.
• When two ligands X, Y bind to different sites on the same receptor R, linkage occurs if
they influence each other’s binding constant
It manifests itself when we compare the free energies ΔG(X), ΔG(Y) to bind each ligand
separately and the free energy ΔG(X, Y) to bind them simultaneously.
If the difference ΔGXY = ΔG(X, Y) − ΔG(X) − ΔG(Y) is nonzero, there is linkage, or
couplingbetween the ligands.
negative ΔGXY (respectively, positive) indicates cooperative (anticooperative) binding
• Linkage can be “homotropic” (X and Y are the same species) or heterotropic (X and Y are
different species).
15. 1.10 ALLOSTERY AND LINKAGE
• ΔGXY is also the free energy for the reaction XR + YR ⇋ R + XRY
(-) system favors the right-hand state, R + XYR
• Cooperativity:whenever there are two conformations (R and T, say), with different binding
affinities for one or both ligands: ΔGR(X) ≠ ΔGT(X) and/or ΔGR(Y) ≠ ΔGT(Y)
• X and Y can be as small as two oxygen molecules targeting hemoglobin, or they can be as
complex as a tRNA and a ribosomal subunit, brought together by a translational GTPase
• Allostery is of particular interest for drug design, since it implies that more than one site
can be targeted for inhibitor or antagonist binding
the existence of a large, delocalized, conformational transition implies that still other sites
can be targeted, to block the transition and trap the system, either in its initial
conformation or in an intermediate conformation along the transition path
• Conformational trapping of kinases and ATPases/GTPases in an inactive, OFF state is an
established therapeutic strategy
16. 1.10 ALLOSTERY AND LINKAGE
• For a kinase or ATPase, we can assume the ligands are ATP and ADP the ON but not the OFF
conformation is active for binding a second partner, and ATP has a greater tendency than ADP
to stabilize the ON conformation and activate protein
ATP preference of each state by the binding free energy differences: ΔΔGON = ΔGON(ATP) −
ΔGON (ADP), and similarly for OFF
We characterize the ligand preference of each state by the free energy differences: ΔΔGATP =
ΔGATP(ON) − ΔGATP(OFF), and similarly for ADP
The overall specificity : ΔΔΔG = GATP − GADP = GON − GOFF ≤ 0
ΔΔΔG is negative by definition of the ON/OFF states; a large magnitude indicates a large
ATPase specificity
if ON and OFF both have large preferences for their respective nucleotides, ΔΔGON is large
and negative, while ΔΔGOFF is large and positive, so that ΔΔΔG is large and negative
17. 1.10 ALLOSTERY AND LINKAGE
overall ATP/ADP binding:ΔΔGbind = ΔGbind(ATP) − ΔGbind(ADP)
x(ANP) = G(ON:ANP) − G(OFF:ANP)
x(ATP) − x(ADP) =ΔΔΔG ≤ 0,
GON ≤ Gbind ≤ GOFF
• One important route is to engineer inhibitors that act by stabilizing the inactive kinase conformation,
like the anticancer drug imatinib : different ON/OFF populations for different kinases will produce
binding specificity.
• Binding specificity for a particular kinase K, compared to another kinase K’, will be achieved if the free
energies of the OFF states are sufficiently different, even if the inhibitor binding sites are conserved
and make the same contacts
• The inhibitor will bind preferentially to the kinase with the most stable OFF conformation, say K.
• Interestingly, the K/K′ binding free energy difference will actually report on the ON/OFF free energy
difference in apo-K’ (and different inhibitors will report the same value)