AGI, A PREVIOUSLY UNREPORTED DROSOPHILA-MELANOGASTER ALPHA-GLUCOSIDASE - PARTIAL-PURIFICATION, CHARACTERIZATION, AND CYTOGENETIC MAPPING

Inbred Drosophila melanogaster stocks were surveyed for alpha-glucosid ases with nondenaturing gel electrophoresis using a fluorogenic substr ate to stain the gels. The glucosidase most active under these conditi ons is polymorphic. We established that the polymorphism is genetic in origin and that the glucosidase was not likely to be a previously cha racterized enzyme. The gene encoding the enzyme was mapped cytogenetic ally to 33 A1-2- 33A8-B1, confirming that this is an enzyme not yet re ported in D. melanogaster. The enzyme was partially purified by elutio n from nondenaturing gels, which enabled us to establish that it has o ptimal activity at pH 6 and interacts most strongly with alpha-1-4 glu cosides. A developmental and tissue survey suggested that this enzyme could have a purely digestive role or be involved in carbohydrate meta bolism inside the organism. We propose that this enzyme is involved in either starch digestion or glycogen metabolism.