MCAT Biochemistry Question 11: Answer and Explanation

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Question: 11

11. Adding concentrated strong base to a solution containing an enzyme often reduces enzyme activity to zero. In addition to causing protein denaturation, which of the following is another plausible reason for the loss of enzyme activity?

  • A. Enzyme activity, once lost, cannot be recovered.
  • B. The base can cleave peptide residues.
  • C. Adding a base catalyzes protein polymerization.
  • D. Adding a base tends to deprotonate amino acids on the surface of proteins.

Correct Answer: B

Explanation:

Bases can catalyze peptide bond hydrolysis. Choice (A) is incorrect: enzyme activity can be recovered in at least some cases. Choice (D) is a true statement, but fails to explain the loss of enzyme activity.

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