Caspases and apoptosis

Caspases are a kind of proteases, which are in form of zymogens in cells and have Cys activating site and substrate lysing site. It will result in apoptosis when caspases lyse their special substrates in cells. Four amino acid residues of N terminal of lysing site determine the substrate specificity of caspsaes. The substrate lysing site from one to several of caspases usually lies behind Asp residue in the primary structure of target proteins. As central effetors of apoptosis, caspases bring important function into play in the start ups and courses of apoptosis. Activation of caspase zymogens depends on processing by an upstream caspase, induced proximity or association with a regulatory subunit, which can induce happening of apoptosis. Apoptosis is the essential character for cells. This review summarizes the enzymes and biochemical mechanisms about apoptosis.