BIOL 302 1st Edition Lecture 11Outline of Last Lecture I. EnzymesII. Enzyme KineticsIII. Michaelis-Menton plotIV. Lineweaver Burke PlotV. Review for first testOutline of Current Lecture VI. Michaelis-Menton PlotVII. Lineweaver-Burke PlotVIII. Enzyme inhibitionCurrent LectureIX. Michaelis-Menten PlotA. Relates reaction velocity and substrate concentrationX. Michaelis-Menten PlotA. Graphical relationship between reaction velocity and substrate concentrationXI. Finding Km and vmaxA. Linearize the MM equationB. Take reciprocal of both sides of equationRearrangeC. where y = 1/vo and x = 1/[S]XII. Lineweaver-Burke PlotA. Also called a double reciprocal plotXIII. Clicker question: Please determine KMA. 4 mMB. 1 mMC. 0.5 mMD. 0.25 mME. -0.25 mM1. Intercept on 1/[S] axis is 1/KMXIV. Clicker question: Please determine vmaxA. 4 mM/sB. 1 mM/sC. 0.5 mM/sD. 0.25 mM/sE. -0.25 mM/sXV. Enzyme InhibitionA. Noncovalent binding:1. Competitive (I binds only to E)2. Uncompetitive (I binds only to ES)3. Noncompetitive (I binds to E or ES)4. Transition State Analogue5. Covalent binding – irreversible6. Group Specific7. SuicideXVI. Enzyme Inhibition – REVERSIBLEA. Competitive Inhibition1. A substance that competes directly with a normal substrate for an enzyme’s substrate-binding site is known as a competitive inhibitor.2. A competitive inhibitor acts by reducing the concentration of free enzyme available for substrate binding.XVII. Competitive inhibitors often resemble the substrate XVIII. CompetitiveInhibitionXIX. Uncompetitive InhibitionXX. Uncompetitive InhibitionA. A compound that binds directly to the enzyme-substrate complex but not to the free enzyme.B. Vmax, and Km decreaseC. The decrease in Km results from the reaction of ES + I to form ESI that uses up ES, causing the substrate binding reaction, E + S = ES, to proceed further to the rightXXI. Noncompetitive InhibitionXXII. Noncompetitive InhibitionXXIII. Transition State AnalogXXIV. Irreversible - Substrate AnalogXXV. Clicker question: How to describe this empirical plot?A. LinearB. HyperbolicC. SigmoidalD. OtherXXVI. Clicker question: Why do we measure the initial velocity V0 of a reaction, and not the reaction rate at equilibrium? A. Because V0 is dependent on the substrate concentration.B. Because V0 allows us to only consider the forward reaction.C. Because V0 is more difficult to measure the reaction rate at equilibrium.D. All of the above XXVII. Clicker question: Which of the following assumptions does the Michaelis Menten equation make?A. The concentration of enzyme is negliglible compared to the concentration of the substrateB. All enzyme is bound to substrate.C. The formation of product is faster than the backward reaction.D. All of the aboveXXVIII. Clicker question: E+S and [ES] are in steady state. Why are [ES] and [E+P] not in steady state? A. Because formation of [ES] is the slowest, rate limiting stepB. Because we are looking at V0 , which means we can ignore the back reaction.C. Once the product is formed, it is not converted back to the substrate.XXIX. Clicker question: Why is the enzymatic activity of enzymes often a bell-shaped curve when monitored dependent on pH?A. The pH will change the surface charge of the enzyme and will alter its solubility.B. The enzyme will denature dependent on the pH and loose activityC. Catalytic residues at the active site are often charged residues, and their charge depends on the pHD. The pH can alter the structure of the catalytic siteE. All of the aboveXXX. Clicker question: Which type of inhibitor can only bind to the enzyme, but not to the enzyme substrate complex?A. uncompetetiveB. noncompetetiveC. competetiveD. covalentE. All of the aboveXXXI. Clicker question: A hydrogen bond can be formed by the side chains of the following amino acid pairs?A. F and KB. M and L C. Y and DD. S and IE. A and GXXXII. Clicker question: Hemoglobin’s affinity for oxygenA. Is higher than myoglobinB. Is higher than of fetal hemoglobinC. Decreases if already one of the subunits has oxygen boundD. Increases in lower pH of tissuesE.Decreases if 2,3 BPG is