What might be the most useful in determining the amino acid residues of an enzyme catalyzed reaction?

Unfold the enzyme with urea and 2-mercaptoethanol. Then incubate and crystallize it in the presence of the substrate followed by X-ray crystallography.

b. Use an irreversible inhibitor that reacts with the side chains of specific amino acids.

c. Determine the entire primary structure of the protein.

d. Use a competitive inhibitor and plot the rate vs concentration of inhibitor.