ENZYME KINETICS. Medical Biochemistry, Lecture 24
|
|
- Charlene Cannon
- 5 years ago
- Views:
Transcription
1 ENZYME KINETICS Medical Biochemistry, Lecture 24
2 Lecture 24, Outline Michaelis-Menten kinetics Interpretations and uses of the Michaelis- Menten equation Enzyme inhibitors: types and kinetics
3 Enzyme Kinetics Equation
4 Michaelis-Menten Equation
5 Initial Velocity (v o ) and [S] The concentration of substrate [S] present will greatly influence the rate of product formation, termed the velocity (v) of a reaction. Studying the effects of [S] on the velocity of a reaction is complicated by the reversibility of enzyme reactions, e.g. conversion of product back to substrate. To overcome this problem, the use of initial velocity (v o ) measurements are used. At the start of a reaction, [S] is in large excess of [P], thus the initial velocity of the reaction will be dependent on substrate concentration
6 Michaelis-Menten Curve
7 Initial Velocity (v o ) and [S] (cont) When initial velocity is plotted against [S], a hyperbolic curve results, where V max represents the maximum reaction velocity. At this point in the reaction, if [S] >> E, all available enzyme is "saturated" with bound substrate, meaning only the ES complex is present.
8 Michaelis-Menten Curve
9 Substrate Saturation of an Enzyme A. Low [S] B. 50% [S] or K m C. High, saturating [S]
10 Steady State Assumption The M-M equation was derived in part by making several assumptions. An important one was: the concentration of substrate must be much greater than the enzyme concentration. In the situation where [S] >> [E] and at initial velocity rates, it is assumed that the changes in the concentration of the intermediate ES complex are very small over time (v o ). This condition is termed a steady-state rate, and is referred to as steady-state kinetics. Therefore, it follows that the rate of ES formation will be equal to the rate ES breakdown.
11 Michaelis-Menten Equation Derivation Rate of ES formation = k 1 ([E T ] - [ES])[S] (where [E T ] is total concentration of enzyme E and k -2 is considered neglible) Rate of ES breakdown to product = k - 1[ES] + k 2 [ES]
12 Michaelis-Menten Equation Derivation (cont) Thus for the steady state assumption: k 1 ([E T ] - [ES])[S] = k -1 [ES] + k 2 [ES] This equation is the basis for the final Michaelis- Menten following algebraic rearrangement and substitution of K m and V max terms.
13 Meaning of K m An important relationship that can be derived from the Michaelis-Menten equation is the following: If v o is set equal to 1/2 V max, then the relation V max /2 = V max [S]/K m + [S] can be simplied to K m + [S] = 2[S], or K m = [S]. This means that at one half of the maximal velocity, the substrate concentration at this velocity will be equal to the K m. This relationship has been shown experimentally to be valid for many enzymes much more complex in regards to the number of substrates and catalytic steps than the simple single substrate model used to derive it.
14 Meaning of K m (cont) The significance of K m will change based on the different rate constants and which step is the slowest (also called the rate-limiting step). In the simplest assumption, the rate of ES breakdown to product (k 2 ) is the ratedetermining step of the reaction, so k -1 >> k 2 and K m = k -1 /k 1. This relation is also called a dissociation constant for the ES complex and can be used as a relative measure of the affinity of a substrate for an enzyme (identical to K d ). However if k 2 >> k -1 or k 2 and k -1 are similar, then K m remains more complex and cannot be
15 Uses of K m Experimentally, K m is a useful parameter for characterizing the number and/or types of substrates that a particular enzyme will utilize (an example will be discussed). It is also useful for comparing similar enzymes from different tissues or different organisms. Also, it is the K m of the rate-limiting enzyme in many of the biochemical metabolic pathways that determines the amount of product and overall regulation of a given pathway. Clinically, K m comparisons are useful for evaluating the effects mutations have on protein function for some inherited genetic
16 Meaning of V max The values of V max will vary widely for different enzymes and can be used as an indicator of an enzymes catalytic efficiency. It does not find much clinical use. There are some enzymes that have been shown to have the following reaction sequence: In this situation, the formation of product is dependent on the breakdown of an enzyme-product complex, and is thus the rate-limiting step defined by k.
17 Derivation of k cat A more general term has been defined, termed k cat, to describe enzymes in which there are multiple catalytic steps and possible multiple rate-limiting steps. The Michaelis-Menten equation can be substituted with k cat
18 Definition and Use of k cat The constant, k cat (units of sec -1 ), is also called the turnover number because under saturating substrate conditions, it represents the number of substrate molecules converted to product in a given unit of time on a single enzyme molecule. In practice, k cat values (not V max ) are most often used for comparing the catalytic efficiencies of related enzyme classes or among different mutant forms of an enzyme.
19 Two Substrate Reactions Many enzyme reactions involve two or more substrates. Though the Michaelis-Menten equation was derived from a single substrate to product reaction, it still can be used successfully for more complex reactions (by using k cat ). Random Ordered Ping-pong
20 Two Substrate Reactions (cont) In random order reactions, the two substrates do not bind to the enzyme in any given order; it does not matter which binds first or second. In ordered reactions, the substrates bind in a defined sequence, S 1 first and S 2 second. These two reactions share a common feature termed a ternary complex, formed between E, ES 1, ES 2 and ES 1 S 2. In this situation, no product is formed before both substrates bind to
21 Two Substrate Reactions (cont) Another possibility is that no ternary complex is formed and the first substrate S 1 is converted to product P 1 before S 2 binds. These types of reactions are termed ping-pong or double displacement reactions.
22 K m and k cat Example: HSV-1 Thymidine Kinase A phosphorylation kinase reaction: T (thymidine) + ATP is converted to TMP (thymidine monophosphate) + ADP In herpesvirus infected cells, this viral encoded TK phosphorylates the antiviral drug acyclovir; this is the pharmacological basis of most herpesvirus treatments In the last 10 years, this approach has been applied to cancer gene therapies with HSV-TK and ganciclovir
23 Thymidine Kinetic Constants for HSV-1 Thymidine Kinase (ONLY AN EXAMPLE!!) HSV-1TK K m (µm) k cat (s -1 ) k cat / K m Gln-125 WT Asn Glu
24 Ganciclovir Kinetic Constants for HSV-1 Thymidine Kinase (ONLY AN EXAMPLE!) HSV-TK K m (µm) k cat (s -1 ) k cat / K m Gln-125 WT Asn Glu
25 Lineweaver-Burk (double reciprocal plot) If the reciprocal (1/X) of the Michaelis-Menten equation is done, after algebraic simplification the following equation results: This relation is written in the format of the equation for a straight line, y = mx + b, where y = 1/v o, m (slope) = K m /V max, x = 1/[S] and the y-intercept, b = 1/V max. When this relation is plotted,the result is a straight line graph
26 Lineweaver-Burk (double reciprocal plot) (cont)
27 Uses of double reciprocal plot The x intercept value is equal to -1/K m. The biggest advantage to using the double reciprocal plot is a more accurate determination of V max, and hence K m. It is also useful in characterizing the effects of enzyme inhibitors and distinguishing between different enzyme mechanisms.
28 Enzyme Inhibitor Types Inhibitors of enzymes are generally molecules which resemble or mimic a particular enzymes substrate(s). Therefore, it is not surprising that many therapeutic drugs are some type of enzyme inhibitor. The modes and types of inhibitors have been classified by their kinetic activities and sites of actions. These include Reversible Competitive Inhibitors, Reversible Non- Competitive Inhibitors, and Irreversible Inhibitors
29 Definition of K i For reversible inhibitors, a term K i can be determined. For competitive inhibitors, the following relation can be used: K m + I = K m (1 + [I] / K i ) ; (where K m + I is the determined K m in the presence of [I]). Determining the K i for other inhibitor types is related but much more complex and not within the scope of this lecture or course
30 Uses of K i K i values are used to characterize and compare the effectiveness of inhibitors relative to K m. This parameter is especially useful and important in evaluating the potential therapeutic value of inhibitors (drugs) of a given enzyme reaction. For example, K i values are used for comparison of the different types of HIV protease inhibitors. In general, the lower the K i value, the tighter the binding, and hence the more effective an inhibitor is.
31 Competitive Inhibition V max - No change K m INCREASES - indicates a direct interaction of the inhibitor in the active site
32 Reversible Competitive Inhibition Competitive inhibitors compete with the substrate for binding at the active site (as E + I). In the double reciprocal plot for a competitive inhibitor acting at the substrate site for the following reasons, notice with increasing concentration of inhibitor, the V max does not change; however, the K m of the substrate is increased. This also reflects the reversible nature of the inhibitor; there is always some concentration of substrate which can displace
33 Non-Competitive Inhibition V max DECREASES - inhibitor affects rate of reaction by binding to site other than substrate active-site K m - No change
34 Reversible Non-Competitive Inhibition Non-competitive inhibitors combine with both the enzyme (E + I) and the enzyme-substrate (EI + S) complex. The inhibitor binds to a site other that the substrate site, and is thus independent of the presence or absence of substrate. This action results in a conformational change in the protein that affects a catalytic step and hence decreases or eliminates enzyme activity (formation of P). Notice in the reciprocal plot, a non-competitive inhibitor does not affect the binding of the substrate (K m ), but it does result in a decrease in V max. This can be explained by the fact that since inhibitor bound to an enzyme inactivates it, the more EI formed will lower [ES] and
35 Irreversible Inhibitors Irreversible inhibitors generally result in the destruction or modification of an essential amino acid required for enzyme activity. Frequently, this is due to some type of covalent link between enzyme and inhibitor. These types of inhibitors range from fairly simple, broadly reacting chemical modifying reagents (like iodoacetamide that reacts with cysteines) to complex inhibitors that interact specifically and irreversibly with active site amino acids. (termed suicide inhibitors). These inhibitors are designed to mimic the natural substrate in recognition and binding to an enzyme active site. Upon binding and some catalytic modification, a highly reactive inhibitor product is formed that binds irreversibly and inactivates the enzyme. Use of suicide inhibitors have proven to be
36 Irreversible Inhibitor: Allopurinol
37 Irreversible Inhibitor: Penicillin (Ex)
38 Diisopropyl Phosphofluoridate: Irreversible Acetylcholinesterase Inhibitor (Example)
39 Inhibitor Summary REMEMBER - The types of enzyme inhibitors described have been for relatively simple, single substrate-product reactions that obey Michaelis-Menten kinetics. However, not all enzyme inhibitors will necessarily be one type of inhibitor. Especially for some multisubstrate reactions, a particular inhibitor can be competitive for one substrate and noncompetitive with a second or third substrate. Also, suicide inhibitors by design are generally competitive inhibitors of a substrate, and therefore must first bind in the active site.
Enzyme Nomenclature Provides a Systematic Way of Naming Metabolic Reactions
Enzyme Kinetics Virtually All Reactions in Cells Are Mediated by Enzymes Enzymes catalyze thermodynamically favorable reactions, causing them to proceed at extraordinarily rapid rates Enzymes provide cells
More informationAfter lectures by. disappearance of reactants or appearance of. measure a reaction rate we monitor the. Reaction Rates (reaction velocities): To
Revised 3/21/2017 After lectures by Dr. Loren Williams (GeorgiaTech) Protein Folding: 1 st order reaction DNA annealing: 2 nd order reaction Reaction Rates (reaction velocities): To measure a reaction
More informationBiochemistry. Lecture 8 Enzyme Kinetics
Biochemistry Lecture 8 Enzyme Kinetics Why Enzymes? igher reaction rates Greater reaction specificity Milder reaction conditions Capacity for regulation C - - C N 2 - C N 2 - C - C Chorismate mutase -
More informationEnzyme Reactions. Lecture 13: Kinetics II Michaelis-Menten Kinetics. Margaret A. Daugherty Fall v = k 1 [A] E + S ES ES* EP E + P
Lecture 13: Kinetics II Michaelis-Menten Kinetics Margaret A. Daugherty Fall 2003 Enzyme Reactions E + S ES ES* EP E + P E = enzyme ES = enzyme-substrate complex ES* = enzyme/transition state complex EP
More informationMichaelis-Menten Kinetics. Lecture 13: Kinetics II. Enzyme Reactions. Margaret A. Daugherty. Fall Substrates bind to the enzyme s active site
Lecture 13: Kinetics II Michaelis-Menten Kinetics Margaret A. Daugherty Fall 2003 Enzyme Reactions E + S ES ES* EP E + P E = enzyme ES = enzyme-substrate complex ES* = enzyme/transition state complex EP
More informationChapter 6: Outline-2. Chapter 6: Outline Properties of Enzymes. Introduction. Activation Energy, E act. Activation Energy-2
Chapter 6: Outline- Properties of Enzymes Classification of Enzymes Enzyme inetics Michaelis-Menten inetics Lineweaver-Burke Plots Enzyme Inhibition Catalysis Catalytic Mechanisms Cofactors Chapter 6:
More informationEnzymes Part III: Enzyme kinetics. Dr. Mamoun Ahram Summer semester,
Enzymes Part III: Enzyme kinetics Dr. Mamoun Ahram Summer semester, 2015-2016 Kinetics Kinetics is deals with the rates of chemical reactions. Chemical kinetics is the study of the rates of chemical reactions.
More informationBCMB 3100 Chapters 6,7,8 Enzyme Basics. Six Classes (IUBMB) Kinetics Michaelis-Menten Equation Vo, Km, Vmax, Kcat Lineweaver-Burk Plot
BCMB 3100 Chapters 6,7,8 Enzyme Basics Six Classes (IUBMB) Kinetics Enzymes are biological macromolecules that increase the rate of the reaction. Six major groups of enzymes (pgs. 94-95/98-99) Oxidoreductases:
More information2013 W. H. Freeman and Company. 6 Enzymes
2013 W. H. Freeman and Company 6 Enzymes CHAPTER 6 Enzymes Key topics about enzyme function: Physiological significance of enzymes Origin of catalytic power of enzymes Chemical mechanisms of catalysis
More informationBCMB 3100 Chapters 6,7,8 Enzyme Basics. Six Classes (IUBMB) Kinetics Michaelis-Menten Equation Vo, Km, Vmax, Kcat Lineweaver-Burk Plot
BCMB 3100 Chapters 6,7,8 Enzyme Basics Six Classes (IUBMB) Kinetics Michaelis-Menten Equation Vo, Km, Vmax, Kcat Lineweaver-Burk Plot Enzymes are biological macromolecules that increase the rate of the
More informationBCMB 3100 Chapters 6,7,8 Enzyme Basics. Six Classes (IUBMB) Kinetics Michaelis-Menten Equation Vo, Km, Vmax, Kcat Lineweaver-Burk Plot
BCMB 3100 Chapters 6,7,8 Enzyme Basics Six Classes (IUBMB) Kinetics Michaelis-Menten Equation Vo, Km, Vmax, Kcat Lineweaver-Burk Plot Enzymes are biological macromolecules that increase the rate of the
More informationChapter 8. Enzymes: basic concept and kinetics
Chapter 8 Enzymes: basic concept and kinetics Learning objectives: mechanism of enzymatic catalysis Michaelis -Menton Model Inhibition Single Molecule of Enzymatic Reaction Enzymes: catalysis chemical
More informationLecture 11: Enzymes: Kinetics [PDF] Reading: Berg, Tymoczko & Stryer, Chapter 8, pp
Lecture 11: Enzymes: Kinetics [PDF] Reading: Berg, Tymoczko & Stryer, Chapter 8, pp. 216-225 Updated on: 2/4/07 at 9:00 pm Key Concepts Kinetics is the study of reaction rates. Study of enzyme kinetics
More informationIt is generally believed that the catalytic reactions occur in at least two steps.
Lecture 16 MECHANISM OF ENZYME ACTION A chemical reaction such as A ----> P takes place because a certain fraction of the substrate possesses enough energy to attain an activated condition called the transition
More informationCHM333 LECTURES 14 & 15: 2/15 17/12 SPRING 2012 Professor Christine Hrycyna
ENZYME KINETICS: The rate of the reaction catalyzed by enzyme E A + B P is defined as -Δ[A] or -Δ[B] or Δ[P] Δt Δt Δt A and B changes are negative because the substrates are disappearing P change is positive
More informationENZYME KINETICS. What happens to S, P, E, ES?
ENZYME KINETICS Go to lecture notes and/or supplementary handouts for the following: 1 Basic observations in enzyme inetics 2 Michaelis-Menten treatment of enzyme inetics 3 Briggs-Haldane treatment of
More informationLecture 15 (10/20/17) Lecture 15 (10/20/17)
Reading: Ch6; 98-203 Ch6; Box 6- Lecture 5 (0/20/7) Problems: Ch6 (text); 8, 9, 0,, 2, 3, 4, 5, 6 Ch6 (study guide-facts); 6, 7, 8, 9, 20, 2 8, 0, 2 Ch6 (study guide-applying); NEXT Reading: Ch6; 207-20
More informationProteins Act As Catalysts
Proteins Act As Catalysts Properties of Enzymes Catalyst - speeds up attainment of reaction equilibrium Enzymatic reactions -10 3 to 10 17 faster than the corresponding uncatalyzed reactions Substrates
More informationBiochemistry. Lecture 8
Biochemistry Lecture 8 Why Enzymes? igher reaction rates Greater reaction specificity Milder reaction conditions Capacity for regulation C - - C N 2 - C N 2 - C - C Chorismate mutase - C - C - C Metabolites
More informationAffinity labels for studying enzyme active sites. Irreversible Enzyme Inhibition. Inhibition of serine protease with DFP
Irreversible Enzyme Inhibition Irreversible inhibitors form stable covalent bonds with the enzyme (e.g. alkylation or acylation of an active site side chain) There are many naturally-occurring and synthetic
More informationClass Business. I will have Project I graded by the end of the week. The discussion groups for Project 2 are cancelled
Quiz 1 Class Business I will have Project I graded by the end of the week. Project 2 is due on 11/15 The discussion groups for Project 2 are cancelled There is additional reading for classes held on 10/30
More informationBMB Lecture 9
BMB 178 2018 Lecture 9 Class 11, November 7, 2018 Steady-state kinetics (I) Case 3. Viscosity Variation If k cat /K m decreases with increasing viscosity, then the reaction is diffusion-limited (S binding
More informationBiochemistry Enzyme kinetics
1 Description of Module Subject Name Paper Name Module Name/Title Enzyme Kinetics Dr. Vijaya Khader Dr. MC Varadaraj 2 1. Objectives 2. Enzymes as biological catalyst 3. Enzyme Catalysis 4. Understanding
More informationPart II => PROTEINS and ENZYMES. 2.7 Enzyme Kinetics 2.7a Chemical Kinetics 2.7b Enzyme Inhibition
Part II => PROTEINS and ENZYMES 2.7 Enzyme Kinetics 2.7a Chemical Kinetics 2.7b Enzyme Inhibition Section 2.7a: Chemical Kinetics Synopsis 2.7a - Chemical kinetics (or reaction kinetics) is the study of
More informationLecture 13: Data Analysis for the V versus [S] Experiment and Interpretation of the Michaelis-Menten Parameters
Biological Chemistry Laboratory Biology 3515/Chemistry 3515 Spring 2018 Lecture 13: Data Analysis for the V versus [S] Experiment and Interpretation of the Michaelis-Menten Parameters 20 February 2018
More informationEnzymes II. Dr. Mamoun Ahram Summer, 2017
Enzymes II Dr. Mamoun Ahram Summer, 2017 Kinetics Kinetics is deals with the rates of chemical reactions. Chemical kinetics is the study of the rates of chemical reactions. For the reaction (A P), The
More informationOverview of Kinetics
Overview of Kinetics [P] t = ν = k[s] Velocity of reaction Conc. of reactant(s) Rate of reaction M/sec Rate constant sec -1, M -1 sec -1 1 st order reaction-rate depends on concentration of one reactant
More informationC a h p a t p e t r e r 6 E z n y z m y e m s
Chapter 6 Enzymes 1. An Introduction to Enzymes Enzymes are catalytically active biological macromolecules Enzymes are catalysts of biological systems Almost every biochemical reaction is catalyzed by
More informationA. One-Substrate Reactions (1) Kinetic concepts
A. One-Substrate Reactions (1) Kinetic concepts (2) Kinetic analysis (a) Briggs-Haldane steady-state treatment (b) Michaelis constant (K m ) (c) Specificity constant (3) Graphical analysis (4) Practical
More informationReading for today: Chapter 16 (selections from Sections A, B and C) Friday and Monday: Chapter 17 (Diffusion)
Lecture 29 Enzymes Reading for today: Chapter 6 (selections from Sections, B and C) Friday and Monday: Chapter 7 (Diffusion) 4/3/6 Today s Goals Michaelis-Menten mechanism for simple enzyme reactions:
More informationBiochemistry 462a - Enzyme Kinetics Reading - Chapter 8 Practice problems - Chapter 8: (not yet assigned); Enzymes extra problems
Biochemistry 462a - Enzyme Kinetics Reading - Chapter 8 Practice problems - Chapter 8: (not yet assigned); Enzymes extra problems Introduction Enzymes are Biological Catalysis A catalyst is a substance
More informationBMB Lectures 9-10 October 25 and 27, Steady-state kinetics
BMB 178 2017 Lectures 9-10 October 25 and 27, 2017 Steady-state kinetics Steady State Kinetics 1. Rate equations 2. Kinetic shortcuts 3. Positional isotope exchange 4. Inhibition Definition of steady state:
More informationChemistry 112 Chemical Kinetics. Kinetics of Simple Enzymatic Reactions: The Case of Competitive Inhibition
Chemistry Chemical Kinetics Kinetics of Simple Enzymatic Reactions: The Case of Competitive Inhibition Introduction: In the following, we will develop the equations describing the kinetics of a single
More informationAli Yaghi. Gumana Ghashan. Mamoun Ahram
21 Ali Yaghi Gumana Ghashan Mamoun Ahram Kinetics The study of Kinetics deals with the rates of chemical reactions. Chemical kinetics is the study of the rate of chemical reactions. For the reaction (A
More informationLecture 16 (10/23/17) Lecture 16 (10/23/17)
Lecture 16 (10/23/17) Reading: Ch6; 207-210 Ch6; 192-193, 195-196, 205-206 Problems: Ch6 (text); 18, 19, 20, 21, 22 Ch6 (study guide-facts); 9, 11 Ch6 (study guide-applying); 2 NEXT Reading: Ch6; 213-218
More informationLecture 12: Burst Substrates and the V vs [S] Experiment
Biological Chemistry Laboratory Biology 3515/Chemistry 3515 Spring 2019 Lecture 12: Burst Substrates and the V vs [S] Experiment 14 February 2019 c David P. Goldenberg University of Utah goldenberg@biology.utah.edu
More informationFrom Friday s material
5.111 Lecture 35 35.1 Kinetics Topic: Catalysis Chapter 13 (Section 13.14-13.15) From Friday s material Le Chatelier's Principle - when a stress is applied to a system in equilibrium, the equilibrium tends
More informationEffect of Temperature Increasing the temperature increases the energy in the system. Two effects kinetic. denaturing
Effect of Temperature Increasing the temperature increases the energy in the system Two effects kinetic denaturing Kinetic effect Increased motion of molecules Increased collisions between enzyme/substrate
More informationBiochemistry 3100 Sample Problems Binding proteins, Kinetics & Catalysis
(1) Draw an approximate denaturation curve for a typical blood protein (eg myoglobin) as a function of ph. (2) Myoglobin is a simple, single subunit binding protein that has an oxygen storage function
More informationPAPER No. : 16, Bio-organic and bio-physical chemistry MODULE No. :21, Bisubstrate Reactions
Subject Paper No and Title Module No and Title Module Tag 16- Bio-Organic & Bio-Physical M-21 Bisubstrate Reactions CHE_P16_M21 TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction 3. Bisubstrate reactions
More informationEnzymes and Enzyme Kinetics I. Dr.Nabil Bashir
Enzymes and Enzyme Kinetics I Dr.Nabil Bashir Enzymes and Enzyme Kinetics I: Outlines Enzymes - Basic Concepts and Kinetics Enzymes as Catalysts Enzyme rate enhancement / Enzyme specificity Enzyme cofactors
More informationPrevious Class. Today. Michaelis Menten equation Steady state vs pre-steady state
Previous Class Michaelis Menten equation Steady state vs pre-steady state Today Review derivation and interpretation Graphical representation Michaelis Menten equations and parameters The Michaelis Menten
More informationBioengineering Laboratory I. Enzyme Assays. Part II: Determination of Kinetic Parameters Fall Semester
Bioengineering Laboratory I Enzyme Assays Part II: Determination of Kinetic Parameters 2016-2017 Fall Semester 1. Theoretical background There are several mathematical models to determine the kinetic constants
More informationTwo requirements for life: Self-replication and appropriate catalysis. A. Most enzymes (def.: biological catalysts) are proteins
Enzymes We must be able to enhance the rates of many physical and chemical processes to remain alive and healthy. Support for that assertion: Maladies of genetic origin. Examples: Sickle-cell anemia (physical)
More informationBIOCHEMISTRY/MOLECULAR BIOLOGY
Enzymes Activation Energy Chemical reactions require an initial input of energy activation energy large biomolecules are stable must absorb energy to break bonds cellulose energy CO 2 + H 2 O + heat Activation
More informationChem Lecture 4 Enzymes Part 2
Chem 452 - Lecture 4 Enzymes Part 2 Question of the Day: Is there some easy way to clock how many reactions one enzyme molecule is able to catalyze in an hour? Thermodynamics I think that enzymes are molecules
More informationBiochemical Kinetics: the science that studies rates of chemical reactions An example is the reaction (A P), The velocity, v, or rate, of the
Biochemical Kinetics: the science that studies rates of chemical reactions An example is the reaction (A P), The velocity, v, or rate, of the reaction A P is the amount of P formed or the amount of A consumed
More informationUnit 3. Enzymes. Catalysis and enzyme kinetics.
Unit 3 Enzymes. Catalysis and enzyme kinetics. OUTLINE 3.1. Characteristics of biological catalysts. Coenzymes, cofactors, vitamins Enzyme nomenclature and classification 3.2. Enzyme catalysis. Transition
More informationCHEM April 10, Exam 3
Name CHEM 3511 April 10, 2009 Exam 3 Name Page 1 1. (12 points) Give the name of your favorite Tech professor and in one sentence describe why you like him/her. 2. (10 points) An enzyme cleaves a chemical
More informationEnzyme Kinetics: The study of reaction rates. For each very short segment dt of the reaction: V k 1 [S]
Enzyme Kinetics: The study of reaction rates. For the one-way st -order reaction: S the rate of reaction (V) is: V P [ P] moles / L t sec For each very short segment dt of the reaction: d[ P] d[ S] V dt
More informationMichaelis-Menton kinetics
Michaelis-Menton kinetics The rate of an enzyme catalyzed reaction in which substrate S is converted into products P depends on the concentration of the enzyme E even though the enzyme does not undergo
More informationComputational Biology 1
Computational Biology 1 Protein Function & nzyme inetics Guna Rajagopal, Bioinformatics Institute, guna@bii.a-star.edu.sg References : Molecular Biology of the Cell, 4 th d. Alberts et. al. Pg. 129 190
More informationBIOCHEMISTRY - CLUTCH REVIEW 2.
!! www.clutchprep.com CONCEPT: BINDING AFFINITY Protein-ligand binding is reversible, like a chemical equilibrium [S] substrate concentration [E] enzyme concentration Ligands bind to proteins via the same
More informationChapter 8: An Introduction to Metabolism
Chapter 8: An Introduction to Metabolism Key Concepts 8.1 An organism s metabolism transforms matter and energy, subject to the laws of thermodynamics 8.2 The free-energy change of a reaction tells us
More informationA First Course on Kinetics and Reaction Engineering. Class 9 on Unit 9
A First Course on Kinetics and Reaction Engineering Class 9 on Unit 9 Part I - Chemical Reactions Part II - Chemical Reaction Kinetics Where We re Going A. Rate Expressions - 4. Reaction Rates and Temperature
More informationRate laws, Reaction Orders. Reaction Order Molecularity. Determining Reaction Order
Rate laws, Reaction Orders The rate or velocity of a chemical reaction is loss of reactant or appearance of product in concentration units, per unit time d[p] = d[s] The rate law for a reaction is of the
More informationExam 3 Review (4/12/2011) Lecture note excerpt covering lectures (Exam 3 topics: Chapters 8, 12, 14 & 15)
Exam 3 Review (4/12/2011) Lecture note excerpt covering lectures 17-23 (Exam 3 topics: Chapters 8, 12, 14 & 15) Enzyme Kinetics, Inhibition, and Regulation Chapter 12 Enzyme Kinetics When the concentration
More informationIntroduction and. Properties of Enzymes
Unit-III Enzymes Contents 1. Introduction and Properties of enzymes 2. Nomenclature and Classification 3. Mechanism of enzyme-catalyzed reactions 4. Kinetics of enzyme-catalyzed reactions 5. Inhibition
More informationChapter 6 Overview. Enzymes. Catalysis most important function of proteins. Globular protein Increase rate of metabolic processes
Chapter 6 Overview Enzymes Catalysis most important function of proteins n Enzymes protein catalysts Globular protein Increase rate of metabolic processes Enzymes kinetics info on reaction rates & measure
More informationEnzyme Kinetics. Michaelis-Menten Theory Dehaloperoxidase: Multi-functional Enzyme. NC State University
Enzyme Kinetics Michaelis-Menten Theory Dehaloperoxidase: Multi-functional Enzyme NC State University Michaelis-Menton kinetics The rate of an enzyme catalyzed reaction in which substrate S is converted
More informationProf. Jason D. Kahn Your Signature: Exams written in pencil or erasable ink will not be re-graded under any circumstances.
Biochemistry 461, Section I May 6, 1997 Exam #3 Prof. Jason D. Kahn Your Printed Name: Your SS#: Your Signature: You have 80 minutes for this exam. Exams written in pencil or erasable ink will not be re-graded
More informationSimple kinetics of enzyme action
Simple kinetics of enzyme action It is established that enzymes form a bound complex to their reactants (i.e. substrates) during the course of their catalysis and prior to the release of products. This
More informationLecture 13: Data Analysis and Interpretation of the Michaelis-Menten Parameters
Biological Chemistry Laboratory Biology 3515/Chemistry 3515 Spring 2019 Lecture 13: Data Analysis and Interpretation of the Michaelis-Menten Parameters 19 February 2019 c David P. Goldenberg University
More informationOverview of MM kinetics
Overview of MM kinetics Prepared by Robert L Sinsabaugh and Marcy P Osgood in 2007. Includes assumptions and deriviation of original MM model. Includes limitations and implications of MM application to
More informationLab training Enzyme Kinetics & Photometry
Lab training Enzyme Kinetics & Photometry Qing Cheng Qing.Cheng@ki.se Biochemistry Division, MBB, KI Lab lecture Introduction on enzyme and kinetics Order of a reaction, first order kinetics Michaelis-Menten
More informationEnzyme reaction example of Catalysis, simplest form: E + P at end of reaction No consumption of E (ES): enzyme-substrate complex Intermediate
V 41 Enzyme Kinetics Enzyme reaction example of Catalysis, simplest form: k 1 E + S k -1 ES E at beginning and ES k 2 k -2 E + P at end of reaction No consumption of E (ES): enzyme-substrate complex Intermediate
More informationLecture # 3, 4 Selecting a Catalyst (Non-Kinetic Parameters), Review of Enzyme Kinetics, Selectivity, ph and Temperature Effects
1.492 - Integrated Chemical Engineering (ICE Topics: Biocatalysis MIT Chemical Engineering Department Instructor: Professor Kristala Prather Fall 24 Lecture # 3, 4 Selecting a Catalyst (Non-Kinetic Parameters,
More informationENZYMES. by: Dr. Hadi Mozafari
ENZYMES by: Dr. Hadi Mozafari 1 Specifications Often are Polymers Have a protein structures Enzymes are the biochemical reactions Katalyzers Enzymes are Simple & Complex compounds 2 Enzymatic Reactions
More informationObjectives INTRODUCTION TO METABOLISM. Metabolism. Catabolic Pathways. Anabolic Pathways 3/6/2011. How to Read a Chemical Equation
Objectives INTRODUCTION TO METABOLISM. Chapter 8 Metabolism, Energy, and Life Explain the role of catabolic and anabolic pathways in cell metabolism Distinguish between kinetic and potential energy Distinguish
More informationName Student number. UNIVERSITY OF GUELPH CHEM 4540 ENZYMOLOGY Winter 2002 Quiz #1: February 14, 2002, 11:30 13:00 Instructor: Prof R.
UNIVERSITY OF GUELPH CHEM 4540 ENZYMOLOGY Winter 2002 Quiz #1: February 14, 2002, 11:30 13:00 Instructor: Prof R. Merrill Instructions: Time allowed = 90 minutes. Total marks = 30. This quiz represents
More informationExam 3 11/10/2014 Last Name (PRINT): First Name: Pg Topic Pts Total possible 3 Multiple. 12 choice 4 Multiple. 9 choice 5 Multiple
Last Name (PRINT): First Name: Pg Topic Pts Total possible 3 Multiple 12 choice 4 Multiple 9 choice 5 Multiple 12 choice 6 Multiple 16 choice, start T/F 7 T/F and Fill in Blank 22 8 Binding problems 12
More informationAn Introduction to Metabolism
An Introduction to Metabolism PREFACE The living cell is a chemical factory with thousands of reactions taking place, many of them simultaneously This chapter is about matter and energy flow during life
More informationCHAPTER 1: ENZYME KINETICS AND APPLICATIONS
CHAPTER 1: ENZYME KINETICS AND APPLICATIONS EM 1 2012/13 ERT 317 BIOCHEMICAL ENGINEERING Course details Credit hours/units : 4 Contact hours : 3 hr (L), 3 hr (P) and 1 hr (T) per week Evaluations Final
More information5. Kinetics of Allosteric Enzymes. Sigmoidal Kinetics. Cooperativity Binding Constant
5. Kinetics of Allosteric Enzymes Sigmoidal Kinetics Cooperativity Binding Constant Kinetics of Allosteric Enzymes Contents Definitions Allosteric enzymes Cooperativity Homoallostery Heteroallostery Biphasic
More information2. Under what conditions can an enzyme assay be used to determine the relative amounts of an enzyme present?
Chem 315 In class/homework problems 1. a) For a Michaelis-Menten reaction, k 1 = 7 x 10 7 M -1 sec -1, k -1 = 1 x 10 3 sec -1, k 2 = 2 x 10 4 sec -1. What are the values of K s and K M? K s = k -1 / k
More informationMembrane Proteins: 1. Integral proteins: 2. Peripheral proteins: 3. Amphitropic proteins:
Membrane Proteins: 1. Integral proteins: proteins that insert into/span the membrane bilayer; or covalently linked to membrane lipids. (Interact with the hydrophobic part of the membrane) 2. Peripheral
More informationAn Introduction to Metabolism
An Introduction to Metabolism I. All of an organism=s chemical reactions taken together is called metabolism. A. Metabolic pathways begin with a specific molecule, which is then altered in a series of
More informationEnergy Transformation, Cellular Energy & Enzymes (Outline)
Energy Transformation, Cellular Energy & Enzymes (Outline) Energy conversions and recycling of matter in the ecosystem. Forms of energy: potential and kinetic energy The two laws of thermodynamic and definitions
More informationEnergy Transformation and Metabolism (Outline)
Energy Transformation and Metabolism (Outline) - Definitions & Laws of Thermodynamics - Overview of energy flow ecosystem - Biochemical processes: Anabolic/endergonic & Catabolic/exergonic - Chemical reactions
More informationExam 4 April 15, 2005 CHEM 3511 Print Name: KEY Signature
1) (8 pts) General Properties of Enzymes. Give four properties of enzymaticallycatalyzed reactions. The answers should indicate how enzymatic reactions differ from non-enzymatic reactions. Write four only
More informationChapter 8: An Introduction to Metabolism
AP Biology Reading Guide Name Chapter 8: An Introduction to Metabolism Concept 8.1 An organism s metabolism transforms matter and energy, subject to the laws of thermodynamics 1. Define metabolism. 2.
More informationENZYME KINETICS AND INHIBITION
ENZYME KINETICS AND INHIBITION The kinetics of reactions involving enzymes are a little bit different from other reactions. First of all, there are sometimes lots of steps involved. Also, the reaction
More information!n[a] =!n[a] o. " kt. Half lives. Half Life of a First Order Reaction! Pressure of methyl isonitrile as a function of time!
Half lives Half life: t 1/2 t 1/2 is the time it takes for the concentration of a reactant to drop to half of its initial value. For the reaction A! products Half Life of a First Order Reaction! Pressure
More informationIntroduction to Metabolism (Or Energy Management) Chapter 8
Introduction to Metabolism (Or Energy Management) Chapter 8 Metabolism of the chemical reactions in the organism Building up molecules Breaking down molecules Managing energy and materials Route to end-product
More informationC a h p a t p e t r e r 6 E z n y z m y e m s
Chapter 6 Enzymes 4. Examples of enzymatic reactions acid-base catalysis: give and take protons covalent catalysis: a transient covalent bond is formed between the enzyme and the substrate metal ion catalysis:
More informationCHAPTER 8. An Introduction to Metabolism
CHAPTER 8 An Introduction to Metabolism WHAT YOU NEED TO KNOW: Examples of endergonic and exergonic reactions. The key role of ATP in energy coupling. That enzymes work by lowering the energy of activation.
More informationProgram for the rest of the course
Program for the rest of the course 16.4 Enzyme kinetics 17.4 Metabolic Control Analysis 19.4. Exercise session 5 23.4. Metabolic Control Analysis, cont. 24.4 Recap 27.4 Exercise session 6 etabolic Modelling
More informationBCH 3023 Fall 2008 Exam 2, Form C Name: ANSWER KEY
Name: ANSWER KEY In class, we discussed one method to linearize the Michaelis-Menton equation. There are other methods to do this, one being an Eadie-Hofstee plot. Given the Eadie-Hofstee plot below, answer
More informationBIBC 102, Metabolic Biochemistry Problem Set 1 Fall 2002
Enzymology problems 1)The sweet taste of fresh corn is due to the high level of sugar in the kernal. Storebought corn that has been sitting around for a few days is not as sweet because about 50% of the
More informationENZYME SCIENCE AND ENGINEERING PROF. SUBHASH CHAND DEPARTMENT OF BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY IIT DELHI LECTURE 7
ENZYME SCIENCE AND ENGINEERING PROF. SUBHASH CHAND DEPARTMENT OF BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY IIT DELHI LECTURE 7 KINETICS OF ENZYME CATALYSED REACTIONS (CONTD.) So in the last lecture we
More informationLearning Outcomes. k 1
Module 1DHS - Data Handling Skills Unit: Applied Maths Lecturer: Dr. Simon Hubbard (H13), Email: Simon.Hubbard@umist.ac.uk Title: Equilibria & Michaelis-Menten This lecture and problem class will introduce
More informationPrevious Class. Today. Cosubstrates (cofactors)
Previous Class Cosubstrates (cofactors) Today Proximity effect Basic equations of Kinetics Steady state kinetics Michaelis Menten equations and parameters Enzyme Kinetics Enzyme kinetics implies characterizing
More informationLecture 4 STEADY STATE KINETICS
Lecture 4 STEADY STATE KINETICS The equations of enzyme kinetics are the conceptual tools that allow us to interpret quantitative measures of enzyme activity. The object of this lecture is to thoroughly
More informationDeriving the Michaelis-Menten Equation
Page 1 of 5 Deriving the Michaelis-Menten Equation This page is originally authored by Gale Rhodes ( Jan 2000) and is still under continuous update. The page has been modified with permission by Claude
More informationSIMPLE MODEL Direct Binding Analysis
Neurochemistry, 56:120:575 Dr. Patrick J. McIlroy Supplementary Notes SIMPLE MODEL Direct Binding Analysis The interaction of a (radio)ligand, L, with its receptor, R, to form a non-covalent complex, RL,
More informationCatalysis is Necessary for Life. Chapter 6 Enzymes. Why Study Enzymes? Enzymes are Biological Catalysts
Chapter 6 Enzymes Catalysis is Necessary for Life Definition: a catalyst is a substance that speeds up a chemical reaction, while emerging unchanged at the end Corollary A: a catalyst is never used up,
More informationAn Introduction to Metabolism
An Introduction to Metabolism PREFACE The living cell is a chemical factory with thousands of reactions taking place, many of them simultaneously This chapter is about matter and energy flow during life
More informationENZYMES 2: KINETICS AND INHIBITION. HLeeYu Jsuico Junsay Department of Chemistry School of Science and Engineering Ateneo de Manila University
ENZYMES 2: KINETICS AND INHIBITION HLeeYu Jsuico Junsay Department of Chemistry School of Science and Engineering Ateneo de Manila University 1 REVIEW OF KINETICS (GEN CHEM II) 2 Chemical KineCcs How fast
More informationChapter 6. Ground Rules Of Metabolism
Chapter 6 Ground Rules Of Metabolism Alcohol Dehydrogenase An enzyme Breaks down ethanol and other toxic alcohols Allows humans to drink Metabolism Is the totality of an organism s chemical reactions Arises
More informationMITOCW enzyme_kinetics
MITOCW enzyme_kinetics In beer and wine production, enzymes in yeast aid the conversion of sugar into ethanol. Enzymes are used in cheese-making to degrade proteins in milk, changing their solubility,
More information