Question

Using site-directed mutagenesis, you have created a mutant form of chymotrypsin that has alanine substituted for the usual serine at position 195. Which of the following effects would your expect to observe? a. No effect or slight increase in affinity for substrate coupled to a complete loss of enzyme activity. b. A decrease in the affinity for substrate coupled to a decrease in enzyme activity. c. An increase in the rate of peptide-bond cleavage due to an increase in the rate of acid-base catalysis. d. An increase in the rate of peptide-bond cleavage due to an increase in the rate of covalent catalysis. e. A complete loss of enzyme activity due to the inability to bind substrate

Answer 1

Answer:

The correct answer is - option E.

Explanation:

Serine may not be affected by the mutation as it has no part of the hydrophobic binding site so it won't affect the affinity of the binding of the substrate. The peptide bond-breaking would not occur without the catalytic end or part so the enzyme would be the complete loss of enzyme activity due to site-directed mutagenesis that is created from the chymotrypsin.

Thus, the correct answer is - option E.