Enzyme kinetics -- Michaelis Menten kinetics

Slides:



Advertisements
Similar presentations
Enzyme Kinetics C483 Spring 2013.
Advertisements

The Michaelis-Menten Equation
Biochemistry 2/e - Garrett & Grisham Copyright © 1999 by Harcourt Brace & Company Enzyme Kinetics.
LAB 3 Enzyme Kinetics Studying -galactosidase activity at varying substrate concentrations in the presence and absence of an inhibitor Michaelis-Menten.
Aulani " Biokimia Enzim Lanjut" Presentasi 5 Basic enzyme kinetics Aulanni’am Biochemistry Laboratory Brawijaya University.
Polymerization kinetics
Kinetics: Reaction Order Reaction Order: the number of reactant molecules that need to come together to generate a product. A unimolecular S  P reaction.
Enzyme Kinetic Zhi Hui.
Chapter 7 Chem 341 Suroviec Fall I. Introduction The structure and mechanism can reveal quite a bit about an enzyme’s function.
Enzyme Kinetics. Rate constant (k) measures how rapidly a rxn occurs AB + C k1k1 k -1 Rate (v, velocity) = (rate constant) (concentration of reactants)
Enzymes Have properties shared by all catalysts Enhance the rates of both forward and reverse reactions so equilibrium is achieved more rapidly Position.
Enzyme Kinetics and Catalysis II 3/24/2003. Kinetics of Enzymes Enzymes follow zero order kinetics when substrate concentrations are high. Zero order.
Enzyme Kinetics: Study the rate of enzyme catalyzed reactions. - Models for enzyme kinetics - Michaelis-Menten kinetics - Inhibition kinetics - Effect.
Enzyme Catalysis (26.4) Enzymes are catalysts, so their kinetics can be explained in the same fashion Enzymes – Rate law for enzyme catalysis is referred.
Inhibited Enzyme Kinetics Inhibitors may bind to enzyme and reduce their activity. Enzyme inhibition may be reversible or irreversible. For reversible.
ENZYME KINETIC M. Saifur R, PhD. Course content  Enzymatic reaction  Rate of Enzyme-Catalyzed Reactions  Quatification of Substrate Concentration and.
CH13. Enzymes cXXkcZ2jWM&feature=related.
Chapter 6.3: Enzyme Kinetics CHEM 7784 Biochemistry Professor Bensley.
Chapter 5 (part 2) Enzyme Kinetics.
23.6 Enzymes Three principal features of enzyme-catalyzed reactions: 1. For a given initial concentration of substrate, [S] 0, the initial rate of product.
Kinetics of Enzyme Reactions Srbová Martina. E + S ES E + P k1k1 k -1 k cat rapid reversible reaction slow irreversible reaction Rate of the conversion.
Enzymes II: Enzyme Kinetics
Quiz #3 Define Enzyme Classes Systematic naming –Given a reaction (including names) –Use subclass designation if appropriate Catalytic mechanisms –Define.
Lecture 5: Chemical Reactions Outline: basic concepts Nonlinearities: saturation: Michaelis-Menten kinetics switching: Goldbeter-Koshland.
Rules for deriving rate laws for simple systems 1.Write reactions involved in forming P from S 2. Write the conservation equation expressing the distribution.
Chapter 5 (part 2) Enzyme Kinetics. Rate constant (k) measures how rapidly a rxn occurs AB + C k1k1 k -1 Rate (v, velocity) = (rate constant) (concentration.
Picture of an enzymatic reaction. Velocity =  P/  t or -  S/  t Product Time.
Today we will deal with two important Problems: 1.Law of Mass Action 2. Michaelis Menten problem. Creating Biomodel in Vcell we will solve these two problems.
Enzymes, inhibition. ENZYMES, CATALYSTS OF BIOLOGICAL SYSTEMS 1.Enzymes in general 2. Development of enzymes 3. General mechanisms of enzymes 4. Kinetic.
Enzyme Assay Why and How??. Introduction In most cases, actual molar enzyme concentration is not known. We measure amount of enzyme by its activity in.
QUIZ 1.What is enzyme? 2.What is the function of enzyme? 3.What are the special characteristics of enzyme? 4.What kind of binding energy involve for the.
Lecture – 3 The Kinetics Of Enzyme-Catalyzed Reactions Dr. AKM Shafiqul Islam
Chapter 16 Equilibrium. How do chemical reactions occur? Collision Model Molecules react by colliding into one another. – This explains why reactions.
Predicting Equilibrium. Determine the reaction quotient, Q, for a system. Include: stating the direction the reaction is proceeding towards equilibrium.
Lab: principles of protein purification
Enzyme Kinetics.
Enzyme Kinetics I 10/15/2009. Enzyme Kinetics Rates of Enzyme Reactions Thermodynamics says I know the difference between state 1 and state 2 and  G.
Rmax and Km (26.4) Constants from Michaelis-Menten equation give insight into qualitative and quantitative aspects of enzyme kinetics Indicate if enzyme.
R max and K m (26.4) Constants from Michaelis-Menten equation give insight into qualitative and quantitative aspects of enzyme kinetics Constants – Indicate.
6.1 A Brief Look at Enzyme Energetics and Enzyme Chemistry Converting substrates to product requires intermediate states – Intermediates are less stable.
Enzymes Fall 2007 Lecture 2 Downloaded from
Enzymes and isoenzymes
Enzyme kinetics & Michaelis-Menten Equation Abdul Rehman Abbasi MSc Chemistry Semester – I Preston University Isb.
Enzyme Kinetics Enzyme Kinetics:
Basic enzyme kinetics Concepts building:
Enzyme Kinetics Bwahahahaha!
Basic enzyme kinetics Concepts building:
Modelling Our System Christin S. and Farah V..
Enzymes.
Bioreactors Engineering
Today we will deal with two important Problems:
Lecture 15 Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors.
Enzymes II Dr. Kevin Ahern.
ENZYME INHIBITION.
Enzymes II:kinetics Dr. Nabil Bashir.
Lecture 15 Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors.
Chapter 6 CHM 341 Fall 2016 Suroviec.
13 part 2 Enzyme kinetics 酵素動力學 溫鳳君0993b303 姜喆云0993b039.
(BIOC 231) Enzyme Kinetics
Chapter Three: Enzymes
Chapter Three: Enzymes
Modelling Our System Christin and Farah.
LECTURE 9.4 – EQUILIBRIUM.
Protein Cascades. Protein Cascades Cascades Activator Output.
Lecture 15 Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors.
Studio 9a 10/30/06.
Enzyme Kinetics Velocity (V) = k [S]
Lecture 15 Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors.
23.4 Chain polymerization Occurs by addition of monomers to a growing polymer, often by a radical chain process. Rapid growth of an individual polymer.
Presentation transcript:

Enzyme kinetics -- Michaelis Menten kinetics Two approaches: Rapid equilibrium approach Quasi steady state approach Assumptions: Total enzyme concentration remains constant during the reaction Amount of enzyme is very small compared to amount of substrate The product concentration is so low that the product inhibition is negligible.

where k1= forward rate constant for formation of ES complex k2= backward rate constant for formation of ES complex k3= rate constant for formation of product P

some notations…….. e = concentration of enzyme s = concentration of substrate p = concentration of product (es) = concentration of enzyme substrate complex t = time v = reaction rate or velocity

Michaelis Menten kinetics --Rapid equilibrium approach It is assumed that ES complex is established very rapidly (since this equilibrium step is only the formation of weak interaction between E & S) The product releasing step (k3) is very slow…….which determines the rate The rate of reverse reaction of the second step is negligible

The equilibrium constant The rate of product formation, (mol/ l.s) The total enzyme concentration 1 2 3

Get an expression for (es) in known quantities…… Sub. eqn (1) in (3)

Now sub. the value of (es) in eqn 2. Michaelis Menten Equation 5

Three special cases…….. Case I (s=KM) Therefore…….. is a function of enzyme concentration only A low value of means that the enzyme has high affinity for the substrate Three special cases…….. Case I (s=KM) Case II (s>>KM) Case III (s<<KM)

Case I (s=KM) Eqn. (5) => So when s=KM, the rate of reaction is one half of its maximal value. i.e. at which 50% of enzyme active sites are occupied by substrate

Case II (s>>KM) Eqn. (5) => --------- ZERO ORDER

Case III (s<<KM) Eqn. (5) => ---------FIRST ORDER

Michaelis Menten kinetics --Quasi steady state approach This approach is assumed that the change in the intermediate (transition complex) concentration with respect to time is negligible. (pseudo steady state/quasi steady state)--- Briggs-Haldane approach i.e.

1 1 1

By p.s.s assumption, Eqn 4==>

We know,

sub the value of (es) in (1) Michaelis Menten Equation

Means that ‘S’ is costant…..which is not correct Controversy of Equilibrium approach: by Equilibrium approach, Means that ‘S’ is costant…..which is not correct

This has been rectified by PSS approach….. by PSS assumption

Life of a man…… Before marriage…. After finding a girl….. SPIDERMAN After finding a girl….. SUPERMAN After engagement…. GENTLEMAN After marriage…… WATCHMAN After 10 yrs….. DOBERMAN