| | Re: If the enzyme is Pepsin and the end product is Peptides what is the substrate?
Pepsin, hydrolyzes only peptide bonds present in Protein(Substrate). It does not hydrolyze non-peptide amide or ester linkages.
Pepsin exhibits preferential cleavage for hydrophobic,aromatic residues . Increased susceptibility to hydrolysis occurs if there is a sulfur-containing amino acid close to the peptide bond, which has an aromatic amino acid.
Cleaves Phe-Val, Gln-His, Glu-Ala, Ala-Leu, Leu-Tyr, Tyr-Leu, Gly-Phe, Phe-Phe and Phe-Tyr bonds in the B chain of insulin.
Pepsin will also preferentially cleave at the carboxyl side of phenylalanine and leucine and to a lesser extent at the carboxyl side of glutamic acid residues. Pepsin will not cleave at valine, alanine, or glycine linkages.Amidation of the C-terminal carboxyl group prevents hydrolysis by pepsin.