Answer :
The correct option is A. Trypsin. Trypsin is a protein-digesting enzyme in pancreatic juice.
In pancreatic juice, trypsin is a protein-digesting enzyme. It is initially secreted in an inactive form known as trypsinogen and is activated in the small intestine. Once activated, trypsin catalyzes the hydrolysis of peptide bonds, particularly targeting the carboxyl groups of the basic amino acids lysine and arginine.
Final answer:
A. Trypsin is the protein-digesting enzyme found in pancreatic juice that catalyzes the hydrolysis of peptide bonds, particularly in the basic amino acids lysine and arginine.
Explanation:
The protein-digesting enzyme in pancreatic juice is trypsin. In the process of protein digestion, enzymes such as trypsinogen and chymotrypsinogen are secreted by the pancreas in their inactive forms and are later activated in the small intestine. The enzyme enteropeptidase, secreted by intestinal mucosal cells, converts trypsinogen into its active form, trypsin, which in turn activates other enzymes like chymotrypsinogen to chymotrypsin.
Trypsin then catalyzes the hydrolysis of peptide bonds in protein chains, specifically those involving the carboxyl groups of the basic amino acids lysine and arginine. Additionally, pancreatic juice contains procarboxypeptidase, which is activated by trypsin to carboxypeptidase, an enzyme responsible for cleaving peptide linkages at the free carboxyl end of a polypeptide chain.