Genetic control of soluble NAD-dependent sorbitol dehydrogenase in Drosophila melanogaster

Abstract

Experiments utilizing standard techniques of cell fractionation and disc electrophoresis have revealed the presence of three distinctly different enzymes which catalyze the oxidation of D-sorbitol in crude extracts of Drosophila melanogaster adults. These include (1) a soluble NAD-dependent sorbitol dehydrogenase (NAD-SoDHS), (2) a mitochondrial NAD-dependent sorbitol dehydrogenase (NAD-SoDHm), and (3) a soluble NADP-dependent sorbitol dehydrogenase (NADP-SoDH). The structural gene for NAD-SoDHS has been mapped to a locus between 65.3 and 65.6 on the third chromosome by means of an electrophoretic variant and a low-activity allele. Through the use of segmental aneuploidy, this gene has been localized to the region limited by salivary bands 91B-93F. Because mutants which alter either the activity or electrophoretic effect on the mitochondrial or NADP-dependent forms, it is suggested that the enzymes in this system are coded for autonomously by different genes.