Papain is a sulfhydryl protease from Carica papaya latex. It has a molecular weight of 23 kDa and an optimum pH range of 6.0-7.0. Supplied as a two times crystalline suspension in 50mM sodium acetate, pH 4.5. To insure full activity, the enzyme should be incubated in a solution containing 1.1mM EDTA, 0.067mM mercaptoethanol and 5.5mM cysteine-HCl for 30 minutes. C.A.S.: 9001-73-4