12. Enzymes are biocatalysts that speed up a chemical reaction in biological systems. The path from reactant (S) to product (P) usually involves an energy barrier, called the activation energy or barrier, which must be overcome in order for the reaction to proceed from left (reactant) to right (product). Sketch a generic drawing showing a reaction which is uncatalyzed and one which is catalyzed (plot of free energy versus the reaction coordinate). Be sure to identify the components in the plot.

12. Enzymes are biocatalysts that speed up a chemical reaction in biological systems. The path from reactant (S) to product (P) usually involves an energy barrier, called the activation energy or barrier, which must be overcome in order for the reaction to proceed from left (reactant) to right (product). Sketch a generic drawing showing a reaction which is uncatalyzed and one which is catalyzed (plot of free energy versus the reaction coordinate). Be sure to identify the components in the plot.

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter6: Energy, Enzymes, And Biological Reactions

Section: Chapter Questions

Problem 8TYK: Which of the following statements about the allosteric site is true? a. The allosteric site is a...

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47. Which of the following is true under the following conditions: The enzyme concentration is 5 nM, the substrate concentration is 5 mM, and the KM is 5 mM. (1 nM = 10-9 M, 1 μM=10-6 M, 1 mM = 10-3 M) Group of answer choices Between 0% and 50% of active sites have substrate bound 0% of active sites have substrate bound 50% of active sites have substrate bound 100% of active sites have substrate bound Between 50% and 100% of active sites have substrate bound
24. Researcher X did a series of experiments and determined the following about Enzyme A and its substrate (S). KM - 4 mM Vmax 100 mM/s axis. (. a) Draw the Michealis-Menton plot with all the above information shown. Be sure to label Vmax Rate of neation (mm) rate of react in mm. supstratiate concentration MM/S b) Convert the Michealis-Menton plot into a Lineweaver-Burk plot below, Label the axis. Vmax Rate of reaction (MM) 8 100 90 Go 100 80 - tmax 30 201 c) Using a dotted line, add in how á uncompetitive inhibitor how the rate would look with (S) (MM/S) x 1|S an uncompetitive inhibitor added. 100 KOMI Ke Vmax Vmar Sun competiti 6 • substante (MMIS)
3. Draw a properly-labeled reaction progress diagram with two lines: one line for the enzyme-catalyzed reaction, and one line for the enzyme-uncatalyzed reaction. The simplified expression for the reaction is S→ P. Assume this reaction is thermodynamically favorable. Show all appropriate species for the enzymatic reaction. Then, answer these questions: A) Are AG and AG# the same thing? B) Which of these properties is related to reaction velocity (k), and what equation describes that relationship? C) Finally, exactly how do enzymes speed up reaction rates? In your answer, please provide both a thermodynamic argument AND a structural argument.
24. Consider the figure below, which is an alternate way to depict the energy changes occurring during a reaction from Substrate (S) to Product (P), when uncatalyzed (curve A) and when catalyzed by an enzyme (curve B). Note that curve B is not the same way we modeled an enzyme-catalyzed reaction in class; this model is a different, perhaps slightly more realistic, way of conceptualizing the energy changes over the course of a reaction than what we did in class. S and ES represent the transition states for reaction of the free substrate (S) or the enzyme-substrate complex (ES). T T activation energy for uncatalyzed reaction EST S edhosob nohtum od bluo woH abiow yedio 2 wwolaixa-y odi no vaigin oroda dapng odt ni o nfog) r gibadhoa P B ES EP progress of reaction activation energy for catalyzed reaction a) Explain briefly why, in curve B, the energy state of the enzyme-substrate complex is less than the energy state of the substrate alone. b) Suppose the enzyme in the diagram was mutated…
1. For enzymatic reaction, a mechanism was proposed by Michaelis and Menten as follows: ES k, and k,' ES à E and P k,. E + S a. Use steady state assumption, derive expression for the reaction rate. Where E is concentration of enzyme, S substrate, ES complex of E and S, E = E, – ES. (If you have difficulty in doing it, please consult lecture note) b. Assume K = 0.038 mol.L' at 25 °C, when the substrate concentration is 0.156 Mol.L', the rate of the reaction is 1.21 m mol/L.s. The maximum rate of conversion reaction is reached at high substrate concentrations. Calculate the maximum rate of this enzyme catalyzed reaction.
Suppose an enzyme and its substrate obey the lock and key model of enzyme catalysis. Which of the following would be true of the enzyme U the active site of the enzyme must be flexible O only one substrate could be converted to product by the enzyme the entire enzyme must be rigid the enzyme could bind different substrates if the substrates shared a common motif somewhere in their structures O the active site of the enzyme must be rigid Submit Answer Retry Entire Group 5 more group attempts remaining
1. Can you describe how electrostatic and steric considerations may lead to preferential stabilization of the transition state at an enzyme active site? 2. What factors are involved in “transition-state complementarity”?
5. By using Excel or GoogleSheets. graph the Lineweaver-Burk plots for the behavior of an enzyme for which the following experimental data are available. What are the Km and Kwax values for the inhibited and uninhibited reactions? Is the inhibitor competitive or noncompetitive? [S] (mM) V, No Inhibitor (mmol min-) V, Inhibitor Present (mmol min-') 1 × 10-4 5 × 10-4 1.5 x 10-3 2.5 x 10-3 5 x 10-3 0.026 0.010 0.092 0.136 0.040 0.086 0.150 0.120 0.165 0.142
37. Consider the following energy diagram for an enzyme-catalyzed reaction. D B A C E G Which step is probably the slowest? a. A →B →C b. C D E c. E F G d. G H I
3. Which of the following statements regarding enzymes and transition states is true? a. stabilization of the transition state must be less than stabilization of ES for catalysis to occur b. binding of substrate to an enzyme often causes strain, thus promoting transition state formation c. the transition state conformation of an enzyme catalyzed reaction is identical to the conformation seen in the uncatalyzed transition state d. formation of the transition state always assures that the reaction will proceed to product e. none of the above are true 4. What is the starting point for selection of a suitable ion-exchange chromatography matrix for purification of a recombinant protein? a. Prediction of isoelectric point (pl) from the amino acid sequence. b. Test protein binding to an ion-exchange matrix at a range of pHs and salt concentrations. c. Test protein binding to a selection of anion and cation exchange matrices. d. Pass your sample through a preparative column and elute with a…
When you plot [S] versus initial velocity for an allosteric enzyme, what type of plot arises: * Hyperbolic. Linear. Exponential. Sigmoidal. Discontinuous
1. Consider the following parameters related to an enzyme that follows Michaelis-Menten kinetics for the reaction: k(1) k(2) S ----> ES ----> P k(-1)