Activities of alpha-ketoisovalerate, pyruvate, and alpha-ketoglutarate dehydrogenases in a mutant of Bacillus subtilis.
An acetate-requiring leaky mutant was induced from Bacillus subtilis 168, and activities of its three alpha-keto acid dehydrogenases were compared with the respectives activities of the parent strain. Both pyruvate and alpha-ketoisovalerate dehydrogenase activities in the mutant were consideralby lower, being only 10-17% of those of the parent, but alpha-ketoglutarate dehydrogenase activity was unchanged. These dehydrogenases are complexed composed of three enzymes: a carboxylase, a lipoic reductase-transacylase, and a dihydrolipoyl dehydrogenase. The carboxylase activity of the affected complexes was no different. Total dihydrolipoyl dehydrogenase activity was only one-third. Thus dihydrolipoyl dehydrogenase is the defective enzyme in the two dehydrogenase complexes; the activity remaining in the mutant is accounted for by the activity of the intact alpha-ketoglutarate dehydrogenase.
D000085:Acetates / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology*; D002474:Cell-Free System; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism*; D007658:Ketone Oxidoreductases / Q000378:metabolism*; D009154:Mutation; D011767:Pyruvate Decarboxylase / Q000378:metabolism; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*
D000085:Acetates; D011768:Pyruvate Dehydrogenase Complex; D007658:Ketone Oxidoreductases; D007655:Ketoglutarate Dehydrogenase Complex; D008058:Dihydrolipoamide Dehydrogenase; D011767:Pyruvate Decarboxylase