Question

In chymotrypsin, the enzyme acyl intermediate cleaves more easy than the peptide bond in the substrate, why?

Answer 1

Chymotrypsin is an enzyme that catalyzes the hydrolytic cleavage of the peptide bond after large hydrophobic residues.

It cleaves the carbonyl side of certain peptide bonds primarily by covalent catalysis.
In this mechanism, a nucleophile becomes covalently attached to a substrate in a transition state with an acyl-enzyme. The double bond between the carbon and nitrogen strengthens its bond. Therefore, It's hard to break the peptide bond in the substrate whereas the protein reacts with a water molecule to produce an amino acid and a new smaller protein. As the protein substrate binds to carboxypeptidase, the active site closes in around it. Hydrolysis of the peptide bond is most likely to occur if the terminal residue has an aromatic or bulky hydrocarbon side chain.