Chyomotrypsin catalyze the hydrolysis as the following, which of the following are true?

Question

(A) The specificity pocket is shape- and charge- complementary to aromatic amino acid residues.

(B) Ser195 performs general base catalysis.

(C) His57 residue on the right panel performs general acid catalysis.

(D) Ser195 performs covalent catalysis.

(E) The developing oxyanion hole (right panel) most likely is stabilized by Glutamate or Aspartate residues

Answer 1

Based on the mechanism, I would say the answer is C. The imidazole group of His57 has an extra proton and a positive formal charge, making it acidic. This catalyzes the cleavage of the nitrogen from the polypeptide substrate by allowing the carbonyl to reform, and "kicking off" the amino group.