title: Reversible inhibition of the fatty acid synthetase complex from Mycobacterium smegmatis by palmitoyl-coenzyme A.
abstract: Palmitoyl-CoA dissociates the fatty acid synthetase complex from Mycobacterium smegmatis into inactive subunits of molecular weight 250,000 as determined by sucrose density gradient centrifugation. Palmitoyl-CoA binds to the subunits but the binding can be prevented and reversed by the mycobacterial 3-O-methylmannose-containing polysaccharide. When the palmitoyl-CoA containing inactive subunits were isolated by gel filtration on Sepharose 6B, and then concentrated and dialyzed against 0.5 M phosphate buffer, pH 7.0, containing 3 mM of the complexing agent heptakis-(2,6-di-O-methyl)-beta-cyclodextrin, activity was regenerated to the level of 40 percent of a control sample. The reversibility of the dissociation and inactivation of the synthetase by palmitoyl-CoA suggests that this end product might play a regulatory role by acting as a feedback inhibitor.
mesh_terms: D003065:Coenzyme A / Q000494:pharmacology; D004793:Enzyme Reactivators; D064429:Fatty Acid Synthases / Q000037:antagonists & inhibitors*; D005246:Feedback; D008766:Methylmannosides / Q000494:pharmacology; D008970:Molecular Weight; D009161:Mycobacterium / Q000201:enzymology*; D010169:Palmitic Acids / Q000494:pharmacology*; D011134:Polysaccharides; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D004793:Enzyme Reactivators; D008766:Methylmannosides; D010169:Palmitic Acids; D011134:Polysaccharides; D064429:Fatty Acid Synthases; D003065:Coenzyme A