Role and control of isocitrate lyase in Candida lipolytica.
Mutants of Candida lipolytica that were unable to grow on acetate but able to utilize succinate or glycerol as a sole carbon source were isolated. Amongst the mutants isolated, one strain (Icl-) was specifically deficient in isocitrate lyase activity, whereas another strain (Acos-) was deficient in acetyl coenzyme A synthetase activity. Since the Icl- mutant could not grow either on n-alkane or its derivatives, such as fatty acid and long-chain dicarboxylic acid, any anaplerotic route other than the glyoxylate pathway was inconceivable as far as growth on these carbon sources was concerned. Acetyl coenzyme A is most likely a metabolic inducer of isocitrate lyase and malate synthase, because the Acos- mutant was characterized by the least susceptibility to induction of these enzymes by acetate. The structural gene for isocitrate lyase was most probably impaired in the Icl- mutant, since revertants (Icl-) produced thermolabile isocitrate lyase. The production of isocitrate from n-alkane by the revertants was enhanced in comparison with the parental strain.
D000105:Acetyl Coenzyme A; D000473:Alkanes / Q000378:metabolism; D002175:Candida / Q000201:enzymology* / Q000235:genetics; D002951:Citrates / Q000096:biosynthesis; D004790:Enzyme Induction; D007522:Isocitrate Lyase / Q000378:metabolism*; D007523:Isocitrates / Q000378:metabolism; D008292:Malate Synthase / Q000378:metabolism; D009154:Mutation; D007652:Oxo-Acid-Lyases / Q000378:metabolism*
D000473:Alkanes; D002951:Citrates; D007523:Isocitrates; D000105:Acetyl Coenzyme A; D008292:Malate Synthase; D007652:Oxo-Acid-Lyases; D007522:Isocitrate Lyase