Purification and some properties of alkaline phosphatase from the hepatopancreas of the shrimp Penaeus japonicus (Crustacea: Decapoda)

Abstract Alkaline phosphatase purified from the hepatopancreas of Penaeus japonicus is stable to heating at 65°C for 5 min. The specific activity of the purified enzyme is 25,000 units/mg of protein. After polyacrylamide gel electrophoresis under denaturing conditions, the purified alkaline phosphatase from shrimp was found to consist of deglycosylated monomers of Mr 40,000 and to retain the attachment sites for both sialic acid and phosphatidylinositol. The alkaline phosphatase from shrimp has an isoelectric point (pI) of 7.6 and becomes more alkaline after the removal of either sialic acid or phosphatidylinositol residues.