PURIFICATION AND CHARACTERIZATION OF AN ALPHA-GLUCOSIDASE FROM THE HEPATOPANCREAS OF THE SHRIMP PENAEUS-JAPONICUS (CRUSTACEA, DECAPODA)

1. The alpha-glucosidase purified from the hepatopancreas of Penaeus japonicus is not membrane-bound and labile to heating at 65-degrees-C for 10 min. 2. The specific activity of the purified enzyme is 223 units/mg of protein. After polyacrylamide gel electrophoresis under denaturing conditions, the purified alpha-glucosidase from shrimp was found to consist of monomers of M(r) 105,000. 3. The alpha-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. The shrimp enzyme has the pH optimum at 5.0 and its K(m) was 125-mu-M with 4-methylumbelliferyl-alpha-D-glucoside as substrate.