Glycyl endopeptidase (EC 3.4.22.25, papaya peptidase B, papaya proteinase IV, glycine-specific proteinase, chymopapain, Papaya proteinase 4, PPIV, chymopapain M) is an enzyme. This enzyme catalyses the following chemical reaction Glycyl endopeptidase (EC 3.4.22.25, papaya peptidase B, papaya proteinase IV, glycine-specific proteinase, chymopapain, Papaya proteinase 4, PPIV, chymopapain M) is an enzyme. This enzyme catalyses the following chemical reaction This enzyme is isolated from the papaya plant, Carica papaya.