This document summarizes the mechanism of enzyme action. It discusses how enzymes lower the activation energy of reactions using transition state theory. Enzymes form complexes with substrates at their active sites, enabling reactions through covalent, acid-base, or intramolecular catalysis. As an example, it describes the catalytic mechanism of the serine protease chymotrypsin, which utilizes a catalytic triad of Asp-His-Ser residues to cleave peptide bonds in two steps of covalent catalysis.
Mechanism of enzyme action -
An enzyme attracts substrates to its active site, catalyzes the chemical reaction by which products are formed, and then allows the products to dissociate (separate from the enzyme surface). The combination formed by an enzyme and its substrates is called the enzyme–substrate complex.
Mechanism of enzyme action -
An enzyme attracts substrates to its active site, catalyzes the chemical reaction by which products are formed, and then allows the products to dissociate (separate from the enzyme surface). The combination formed by an enzyme and its substrates is called the enzyme–substrate complex.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
This presentation deals with basics of enzyme kinetics and introduction to various plots which aid in understanding the mechanism of inhibition of enzymes.
Enzymes properties, nomenclature and classificationJasmineJuliet
Enzymes - Definition, Introduction about biocatalysts, Properties of enzymes, Specificity, capacity for regulation, Example for enzyme at specific pH, Nomenclature of enzymes, Systematic name, common name, enzyme commission number, Classification of enzymes: Oxidoreductase, Transferase, lyases, ligases, isomerases, hydrolases.
it is bypass cycle of citric acid cycle.
it give the brief description of glyoxylate cycle.
it is the summary of glyoxylate cycle for m.sc, bsc, science students.
it is very important topic for entrance exam of biology stream.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
This presentation deals with basics of enzyme kinetics and introduction to various plots which aid in understanding the mechanism of inhibition of enzymes.
Enzymes properties, nomenclature and classificationJasmineJuliet
Enzymes - Definition, Introduction about biocatalysts, Properties of enzymes, Specificity, capacity for regulation, Example for enzyme at specific pH, Nomenclature of enzymes, Systematic name, common name, enzyme commission number, Classification of enzymes: Oxidoreductase, Transferase, lyases, ligases, isomerases, hydrolases.
it is bypass cycle of citric acid cycle.
it give the brief description of glyoxylate cycle.
it is the summary of glyoxylate cycle for m.sc, bsc, science students.
it is very important topic for entrance exam of biology stream.
• Enzyme catalysis is the process by which there is an increase in the rate of a reaction through a biological molecule called an enzyme.
• For a reaction to be successful, the molecules of the reactants should contain sufficient energy to cross the energy barrier, i.e., the activation energy.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
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Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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Mechanism of enzyme action
1. MECHANISM OF ENZYME ACTION
2021-2022
SHARDA TARAD
M.SC. CHEMISTRY (SEMESTER-3)
DEPARTMENT OF CHEMISTRY S.P.C.G.C. AJMER
2. CONTENT
1. INTRODUCTION OF ENZYMES
2. TRANSITION-STATE THEORY
3. COVALENT CATALYSIS
4. ACID BASE CATALYSIS
5. INTRAMOLECULAR CATALYSIS
6. EXAMPLE OF CHYMOTRYPSIN ENZYME
3. INTRODUCTION OF ENZYMES
• Biological catalysts
• Neither consumed nor permanently altered
• All enzymes are proteins in nature except ribozymes which are RNA in nature
• Highly efficient
• Act as selective catalysts
• Site where actual Reaction occurs
• Substrate-bound by weak interaction
4. MECHANISM OF ENZYME ACTION
The catalystic efficiency of enzyme is explained
by 2 perspectives:
1.Thermodynamic change
2.Processes at the active site
5. • What is transition-state theory?
• All chemical reaction have eneygy bariers between reactant and
products.
• Activational Barrier:- Differnce in energy level of Transitional state
and Substrate.
SUBSTRATE PRODUCTS
6. • Activation Energy:- of a chemical reaction is the minimum energy that is needed to
make the reaction happen.
• Only a few Substrate can cross this barrier to be converted to Products.
• That is why rate of uncatalyzed reaction is much slow.
• When enzyme is present it provide an alternate pathway for conversion of Substrate
into product.
• Enzymes accelerate reaction rate by providing Transtion state with low activational
energy for formation of products.
• The total energy of the system remains the same equilibrium state is not disturbed
9. • Enzyme from covalent linkages with substrate forming transient enz-subs complex
with very low activational barrier.
• Enzyme is then released unchanged and unconsumed and substrate is converted into
products.
10. ACID BASE CATALYSIS
• Mostly undertaken by oxido-reductases.
• Mostly at the active site, either histidine is present which act both as a proton donor and a
proton acceptor.
11. INTRAMOLECULAR CATALYSIS
• This mechanism is mostly undertaken by ligases.
• The rate of reaction is by bringing substrate closer to each other at the a.site.
• A region of high substrate conc. is produced at the active site..
• The substrates molecule is placed at bond forming distances.
• Since substrate is placed at optimal distances.
• The probability of collision and substrate is eventually converted into
products.
(ORIENTATION AND STERIC EFFECT)
12. Structure of Chymotrypsin
Globular single-domain protein.
Originally synthesized as a 245 residue protein, chymotrypsinogen.
Dipeptides 14-15 and 147-148 are clipped out, transforming the protein into active
chymotrypsin.
Therefore it has 3 chains (red, blue, green) but these are covalently linked by
disulfide bridges.
The reactive serine 195 is located in a cleft on the molecule, the active site.
Ser195 is adjacent to His57 and Asp102 which are responsible for its reactivity.
13. CHYMOTRYPSIN
• Serine protease
• Catalystic mechanism involves Ser residue.
• Utilizes catalytic triad
• Asp102-His57-Ser195
• Ser provides nucleophile(o atom)
• His acts as base catalyst to activate Ser
• Asp stabilizes protonated His
• 2-step reaction covalent catalysis
14. MECHANISM OF CHYMOTRYPSIN
STEP 1: H+ Shift generates Ser-O¯(substrate binding)
STEP 2: Ser-O¯binds to C꓿O(Nucleophilic attack)
STEP 3: Transition state ׀
STEP 4: Peptide bond breaks
15. MECHANISM OF CHYMOTRYPSIN
STEP 5: C-Terminal Peptide leaves
STEP 6: Ionization of water
STEP 7: Transition State װ
STEP 8: N-Terminal peptide leaves
