Purification and characterization of an α-glucosidase from the hepatopancreas of the shrimp Penaeus japonicus (Crustacea: decapoda)

Abstract

1. 1. The α-glucosidase purified from the hepatopancreas of Penaeus japonicus is not membrane-bound and labile to heating at 65°C for 10 min. 2. 2. The specific activity of the purified enzyme is 223 units/mg of protein. After polyacrylamide gel electrophoresis under denaturing conditions, the purified α-glucosidase from shrimp was found to consist of monomers of M r 105,000. 3. 3. The α-glucosidase from shrimp has an isoelectric point (pI) of 3.8 and becomes more alkaline after the removal of sialic acid and phosphoric acid. 4. 4. The shrimp enzyme has the pH optimum at 5.0 and its K m was 125 μM with 4-methylumbelliferyl-alpha- d-glucoside as substrate.