Alpha-D-glucosidase in the midgut of the American cockroach, Periplaneta americana
Katagiri, C.
Insect Biochemistry 92: 205-209
1979
Accession: 037792886
A sugar hydrolyzing enzyme was purified from the midgut of the American cockroach by DEAE-cellulose and affinity column chromatography. Examination of its substrate specificity showed that this enzyme is an .alpha.-D-glucosidase (EC 3.2.1.20). Purified enzyme preparation exhibited a high degree of homogeneity on an acrylamide gel. The preparation was still contaminated with other glycosidases such as trehalase (EC 3.2.1.28), .beta.-D-glucosidase (EC 3.2.1.21) or .alpha.-amylase (EC 3.2.1.1). The isoelectric point of the enzyme was very low, pH 3.54, the pH optimum was 5.8 and the Km value was 5.0 mM for p-nitrophenyl-.alpha.-D-glucopyranoside. The characteristics show that the midgut .alpha.-D-glucosidase was distinct from the serum of .alpha.-D-glucosidase.