Answer to Question #93407 in Biochemistry for Kylie

Question

Discuss the functions of pepsin, trypsin and chymotrypsin.

Answer 1

Pepsin plays a significant digestive role in mammals, including humans. Pepsin is only active in acid environment of the stomach. This enzyme performs one of the important steps in the chain of transformations of food proteins into amino acids. Pepsin catalyzes the hydrolysis of peptide bonds formed by aromatic amino acid residues, breaks down almost all natural proteins into peptides. Some exceptions are keratins, protamines, histones and mucoproteins.

Trypsin catalyzes the hydrolysis of proteins and peptides. It is activated by the intestinal enzyme enteropeptidase. Trypsin mainly hydrolyzes peptide bonds formed by the carboxyl groups of arginine and lysine. It also catalyzes the hydrolysis of ester waxes. It turns the remaining hydrolase proenzymes into active enzymes.

Chymotrypsin is activated by trypsin in the intestine. Chymotrypsins are mostly active against peptide bonds formed by carboxyl groups of aromatic amino acids (phenylalanine, tryptophan, tyrosine).