The activity of an enzyme requires a glutamic acid to display its -COOH functional group in the protonated state. Suppose the pK, of the -COOH group is 4.07. (a) Will the enzyme be more active at pH 3.5 or 4.5? Explain. (b) What fraction of the enzymes will be active at pH = 4.07? Explain. (c) At what pH will the enzyme show 78% of maximal activity?

The activity of an enzyme requires a glutamic acid to display its -COOH functional group in the protonated state. Suppose the pK, of the -COOH group is 4.07. (a) Will the enzyme be more active at pH 3.5 or 4.5? Explain. (b) What fraction of the enzymes will be active at pH = 4.07? Explain. (c) At what pH will the enzyme show 78% of maximal activity?

Introduction to General, Organic and Biochemistry

11th Edition

ISBN:9781285869759

Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Publisher:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar Torres

Chapter23: Enzymes

Section: Chapter Questions

Problem 23.65P

See similar textbooks

Similar questions

In the multienzyme sequence shown below, molecules of D are able to fit to the enzyme E1 and prevent the conversion of A to B. What is this action of E called? AE1BE2CE3D a. effector inhibition b. allosteric inhibition c. feedback inhibition d. competitive inhibition by nonproduct
An enzyme catalyzes the hydrolysis of an ester with a certain activity, but this activity is lost in a 3 M urea solution. What is the most likely explanation for the loss of activity? (A) Urea binds to the active site of the enzyme competitively with the substrate. (B) Urea causes the cleavage of the peptide bonds in the enzyme. (C) Urea causes the enzyme to denature and lose its specific three-dimensional shape. (D) Urea reacts with disulfide bonds in the enzyme.
Oxaloacetate is an inhibitor of succinate dehydrogenase because it is structurally very similar to succinate as shown below. Also, its binding to the enzyme does not involve any covalent bond formation. What type of inhibitor is oxaloacetate? COO | CH₂ 1 CH₂ 1 COO Succinate COO | CH₂ C=O COO Oxaloacetate O a noncompetitive inhibitor both a noncompetitive and an irreversible inhibitor O an irreversible inhibitor O a competitive inhibitor
Will an enzyme inhibited by EDTA, activate a water molecule for direct attack and hydrolysis? Will this enzyme use a covelent intermediate in its mechanism?
What is the expected result if the enzyme monoamine oxidase is treated with the substrate analog named N,N-dimethylpropargylamine? H3C `N I CH3 N,N-dimethylpropargyl amine The product propargyl aldehyde (H-C=C-CH=O) will be formed and released. The product propargyl alcohol (H-CEC-CH₂-OH will be formed and released. The enzyme will be rapidly and covalently (irreversibly) inhibited. The enzyme will be reversibly and competitively inhibited in the presence of this substrate analog. a. b. monoamine oxidase C. d. MAO + O₂
The isoelectric point (pl) of phenylalanine is pH 5.5. Draw the structure of the major form of glutamic acid at pH values of (a) 1 (b) 5.5 (c) 11.0.
The isoelectric point, pl, of the protein trypsin is 10.5, while that of glyceraldehyde-3-phosphate dehydrogenase is 6.55. What is the net charge of trypsin at pH 5.1 ?[ What is the net charge of glyceraldehyde-3-phosphate dehydrogenase at pH 6.1 ?[ The isoelectric point of glutamic acid is 3.22; asparagine, 5.41. During paper electrophoresis at pH 6, toward which electrode does glutamic acid migrate? | During paper electrophoresis at pH 6.5, toward which electrode does asparagine migrate? [
Consider a drug molecule that binds to an enzyme with a Kd of 20.281 nM. If the intracellular concentration of the free drug in a patient is 19.225 nM at equilibrium, what percentage of enzyme molecules are bound to the drug?
*In the presence of saturating amounts of oxaloacetate, the activity of citrate synthase from pig heart tissue shows a sigmoidal dependence on the concentration of acetyl-SCOA as shown below. SCOA is added, the curve shifts to the right and becomes even more sigmoidal. On the basis of these observations, explain how succinyl- SCOA regulates the activity of citrate synthase. Why is succinyl-SCOA an appropriate signal for regulation of the citric acid cycle? does the regulation of citrate synthase control the rate of cellular respiration in pig heart tissue? 100 - 80 succinyl-CoA Activity (% of V, 60 40- No Succinyl-CoA added 20 40 60 80 100 120 [Acetyl-CoAl(pM) - How -
2. Which is a false statement regarding non-competitive enzyme inhibitor? (a) It binds to an allosteric site of the enzyme (b) It does not compete with the natural substrate for binding to the active site of the enzy (c) Its binding to the enzyme can induce a conformational change of the enzyme (d) It can be used in combination therapies with a competitive inhibitor (e) It usually is a mimic of the natural enzyme substrate 3. What is the purpose of structure-activity-relationship (SAR) studies? (a) To identify the drug target (b) To improve the pharmacokinetic properties of the drug (c) To determine which atoms or functional groups are important to the activity of a drug (d) To simplify the synthesis of the drug (e) To optimise activity of the drug
How can the Michaelis constant (Km) be identified and used to represent the affinity between the enzyme and the substrate?
Describe the reactions that you would expect these enzymes to catalyze.(a) Alcohol dehydrogenase (b) Aspartate transaminase(c) Tyrosine-tRNA synthetase (d) Phosphohexose isomerase