Proteolytic activation Many proteins/enzymes are made as inactive precursors that are activated by proteolytic cleavage:after this cleavage the enzymes fold into their catalytically active conformation. Inactive precursors are called proenzymes or zymogens. Proteolytic activation is irreversible -a different mechanism is required for inactivation of the enzyme. Examples:blood clotting,digestive proteases,peptide hormones (insulin),proteins involved in developmental processes (collagen),apoptosis (programmed cell death; caspases)and virus proteases (cuts multidomain viral proteins into their active forms,see 9.1.7). Proteolytic activation • Many proteins/enzymes are made as inactive precursors that are activated by proteolytic cleavage: after this cleavage the enzymes fold into their catalytically active conformation. • Inactive precursors are called proenzymes or zymogens. • Proteolytic activation is irreversible -> a different mechanism is required for inactivation of the enzyme. • Examples: blood clotting, digestive proteases, peptide hormones (insulin), proteins involved in developmental processes (collagen), apoptosis (programmed cell death; caspases) and virus proteases (cuts multidomain viral proteins into their active forms, see 9.1.7)