Hydrolysis within a polypeptide
During protein digestion, peptidases catalyse hydrolysis of the peptide bonds joining amino acids in polypeptides.
Endopeptidases act at peptide bonds within a polypeptide rather than at its terminal ends. Different endopeptidases can target bonds involving particular amino acids.
Breaking these internal bonds divides a long polypeptide into shorter polypeptide chains.
Digestive endopeptidases act in the stomach and small intestine.
Exam Tip: When describing endopeptidase action, identify the position of hydrolysis: the enzyme acts on peptide bonds within the polypeptide chain.