Characterization of a low-activity allele of NADP+-dependent isocitrate dehydrogenase from Drosophila melanogaster.
We have characterized biochemical effects of IdhGB1 in Drosophila melanogaster. This is a "null"-activity allele for NADP+-dependent isocitrate dehydrogenase (NADP-IDH) isolated from a natural population. The homozygous mutant strain has 5% of the NADP-IDH specific activity found in controls and less than 24% of the immunologically cross-reacting material (CRM). This mutation maps to 27.2 on the third chromosome, to the right of h. The biochemical phenotype of this mutant strain includes a coordinate reduction in malic enzyme (ME) specific activity and CRM and an increase in specific activity for the pentose-phosphate shunt enzymes, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase. The Km values for purified NADP-IDH are not different from those found for the purified control enzyme for NADP+ or isocitrate. It is suggested that this allele may represent a cis-acting control mutation for one of at least two loci involved in the production of NADP-IDH in D. melanogaster.
D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics; D007521:Isocitrate Dehydrogenase / Q000235:genetics*; D008291:Malate Dehydrogenase / Q000235:genetics; D008297:Male; D009249:NADP / Q000494:pharmacology; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics
D009249:NADP; D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase