How Is Specificity Determined by Chymotrypsin

Multiple Choice

How is specificity determined by chymotrypsin?

A) interaction of the active site amino acids with the substrate
B) binding of the N-terminus amino acid at the active site
C) covalent binding of a His residue to the substrate
D) large conformational change of a P-loop upon binding of substrate
E) binding of the proper amino acid into a deep pocket on the enzyme