Concept explainers
Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book.
Quantitative Relationships Between Rale Constants to Calculate Km, Kinetic Efficiency (kcat/Km) and Vmax - II Triose phosphate isomerase catalyzes the conversion of glyceraldehyde-3-phosphate to dihydroxy-acetone phosphate.
a. What is Vmax for this enzyme?
b. Assuming 3 nanomoles per mL of enzyme was used in this experiment ([Etotal]) = 3 nanomol/mL), what is kcat for this enzyme?
c. What is the catalytic efficiency (kcat/Km) for triose phosphate isomerase?
d. Does the value of kcat/Km reveal whether triose phosphate isomerase approaches "catalytic perfection"?
e. What determines the ultimate speed limit of an enzyme-catalyzed reaction? That is, what is it that imposes the physical limit on kinetic perfection?
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Chapter 13 Solutions
Biochemistry
- Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Graphical Analysis of MWC Allosteric Enzyme Kinetics (Integrates with Chapter 1.1) Draw both Line weaver-Burk plots and Hanes-Woolf plots for an MWC allosteric enzyme system, showing separate curves for the kinetic response in (a) the absence of any effectors, (b) the presence of allosteric activator Λ, and (c) the presence of allosteric inhibitor I.arrow_forwardAnswers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Quantitative Relationships Between Rate Constants to Calculate Km, Kinetic Efficiency (kcat/Km) and Vmax - VI The enzyme catalase catalyzes the decomposition of hydrogen peroxide: 2H2O22H2O+O2The turnover number (kcat) for catalase is 40,000,000 sec-1. The Km of catalase for its substrate H2O2 is 0.11 M. a. In an experiment using 3 nanomole/L of catalase, what is Vmax? b. What is v when [H2O2] = 0.75 M? c. What is the catalytic efficiency of catalase? d. Does catalase approach catalytic perfection?arrow_forwardAnswers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Determining the Branch Points and Reducing Ends of Amylopectin A 0.2-g sample of amylopectin was analyzed to determine the fraction of the total glucose residues, that are branch points in the structure. The sample was exhaustively methylated and then digested, yielding 50-mol of 2,3-dimethylgluetose and 0.4 mol of 1,2,3,6- letramethylglucose. What fraction of the total residues are branch points? I low many reducing ends does this sample of amylopectin have?arrow_forward
- Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Assessing the Formation and Composition of Limit Dextrins Prolonged exposure of amylopectin to starch phosphorylase yields a substance called a limit dextrin. Describe the chemical composition of limit dextrins. and draw a mechanism for the enzyme-catalyzed rcactioa that can begin the breakdown of a limit dextrin.arrow_forwardAnswers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Calculate the pH in a Muscle Cell from the HPO42-/H2PO4Ratio If the internal pH of a muscle cell is 6.8, what is the [HPO42-]/ [H2PO4-] ratio in this cell?arrow_forwardAnswers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Calculating and Keq for Coupled Reactions For the process A B. Keq (AB) is 0.02 at 370C. For the process B C. Keq (BC)=1000 at 370C. Determine Keq (AC), the equilibrium constant for the overall process A C, from Keq((AB) and (BC). Determine standard-state free energy changes for all three processes, and use G. (AC) to determine Keq (AC). Make sure that ibis value agrees with that determined m part a of this problem.arrow_forward
- Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Quantitative Relationships Between Rate Constants to Calculate Km, Kinetic Efficiency (kcat/Km) and Vmax - I Measurement of the rate constants for a simple enzymatic reaction obeying Michaelis-Menten kinetics gave the following results: k1=2108M1sec1k1=1103sec1k2=5103sec1a. What is Ks, the dissociation constant for the enzyme-substrate complex? b. What is Km, the Michaelis constant for this enzyme? c. What is kcat (the turnover number) for this enzyme? d. What is the catalytic efficiency (kcat/Km) for this enzyme? e. Does this enzyme approach kinetic perfection? (That is, does kcat/Km approach the diffusion-controlled rate of enzyme association with substrate?) f. If a kinetic measurement was made using 2 nanomoles of enzyme per mL and saturating amounts of substrate, what would Vmax equal? g. Again, using 2 nanomoles of enzyme per mL of reaction mixture, what concentration of substrate would give v = 0.75 Vmax? h. If a kinetic measurement was made using 4 nanomoles of enzyme per mL and saturating amounts of substrate, what would Vmax equal? What would Km equal under these conditions?arrow_forwardAnswers to all problems are at the end of this book Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Solving the Sequence of an Oligopeptide From Sequence Analysis Data Analysis of the blood of a catatonic football fan revealed large concentrations of a. psychologic octapeptide. Amino acid analysis of this oclapeplide gave the following results: 2 Ala lArg 1 Asp 1 Mel 2 Tyr I Val 1NH/ The following facts were observed: Partial acid hydrolysis of the octapeptide yielded a dipeptide of the structure Chymolrypsin treatment of the octapeplide yielded two tetrapeptides, each containing an alanine residue. Trypsin treatment of one of the tetrapeptides yielded two dipeptides. Cyanogen bromide treatment of another sample of the same tetrapeplide yielded a tripeplideand free Tyr. N-lerminal analysis of the other tetrapeptide gave Asn. What is the amino acid sequence of this oclapeplide?arrow_forwardAnswers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Plot the Titration Curve for Bicine and Calculate How to Prepare a pH 7.5 Bicine Buffer Solution Bicine (N, N—bis (2-hydroxyethyl) glycine) is another commonly used buffer in biochemistry labs. The structure of Bicine in its fully protonated form is shown here: Draw the titration curve for Bicine. assuming the pA'a for its free COOH group is 2.3 and the pAa for its tertiary amino group is 8.3. Draw the structure of the fully deprotonated form (completely dissociated form) of bicine. You have available a U.l Msolution of Bicine at its isoelectric point (pH|)T 0.1 M solutions of HCI and NaOH. and ample distilled water. Describe the preparation of 1 L of 0.U4 M Bicine buffer. pH 7.5. What is the concentration of the fully protonated form of Bicine in your final buffer solution?arrow_forward
- Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Graphical Analysis of Negative Gooperativity in KNF Allosteric Enzyme Kinetics The KNF model for allosteric transitions includes the possibility of negative cooperativity Draw Lineweaver-Burk and Hanes-Woolf plots for the case of negative cooperatively m substrate binding. (As a point of reference, include a line showing the classic Michaelis-Menten response of v to [S].)arrow_forwardAnswers to all problems are at the end οΓthis book. Detailed solutions are available in the Student Solutions Manual. Study Guide, and Problems Book. Consult the following reference (Samanta U. and Bahnson. B. J., 2008. Crystal structure of human plasma platelet-activating factor acetylhydrolase. Journal of Biological Chemistry 283:31617-3U624). consider the active-site structure of this enzyme in the Light of material in this chapter, and write a detailed mechanism for the PAF acetylhydrolase.arrow_forwardAnswers to all problems are at the end of this book.. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book. Calculating the Composition of Anomeric Sugar Mixtures -D-Glucose has a specific notation, []220, of + 112.20. whereas -D-glucose has a specific notation of +18.70. What is the composition of a mixture of - and -D-glucose, which has a specific notation of 83 .U0?arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning