Involvement of long-chain acyl coenzyme A for lipid synthesis in repression of acetyl-coenzyme A carboxylase in Candida lipolytica.
Mutant strains of Candida lipolytica defective in acyl-CoA synthetase II [acid:CoA ligase (AMP-forming), EC 6.2.1.3] have been isolated. The mutants fail to grow on fatty acid as a sole carbon source but are capable of incorporating exogenous fatty acid into cellular lipids. This observation, together with our previous finding that mutant strains defective in acyl-CoA synthetase I cannot incorporate exogenous fatty acid into cellular lipids but are able to degrade fatty acid via beta-oxidation, indicates the presence of two functionally distinct long-chain acyl-CoA pools in the cell--i.e., one for lipid synthesis and the other for beta-oxidation. Unlike the wild-type and the revertant strains as well as the mutants lacking acyl-CoA synthetase II, the mutants defective in acyl-CoA synthetase I do not exhibit the repression of acetyl-CoA carboxylase [acetyl-CoA:carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] by exogenous fatty acid. Measurement of the two long-chain acyl-CoA pools with the aid of appropriate mutant strains has indicated that the long-chain acyl-CoA to be utilized for lipid synthesis, but not that to be degraded via beta-oxidation, is involved in the repression of acetyl-CoA carboxylase.
D000103:Acetyl-CoA Carboxylase / Q000378:metabolism*; D000214:Acyl Coenzyme A / Q000378:metabolism*; D002175:Candida / Q000201:enzymology*; D003066:Coenzyme A Ligases / Q000235:genetics / Q000378:metabolism*; D004794:Enzyme Repression; D008025:Ligases / Q000378:metabolism*; D050356:Lipid Metabolism; D008055:Lipids / Q000096:biosynthesis*; D010084:Oxidation-Reduction
D000214:Acyl Coenzyme A; D008055:Lipids; D008025:Ligases; D003066:Coenzyme A Ligases; D000103:Acetyl-CoA Carboxylase