title: An essential methionine in pig kidney general acyl-CoA dehydrogenase.
abstract: The flavoprotein pig kidney general acyl-CoA dehydrogenase contains a single catalytically essential methionine residue/FAD which reacts with iodoacetate at pH 6.6. S-Carboxymethylation of this residue generates an inactive enzyme derivative which retains FAD and the tetrameric structure of the native protein. The derivative binds actanoyl-CoA and palmityol-CoA with concomitant perturbation of the flavin chromophore, but the characterisitic spectrum of the reduced enzyme-enoyl-CoA complex is not observed. In addition, octanyol-CoA strongly protects the native enzyme against alkylation with iodoacetate. These results suggest that the methionine residue is within the active center of acyl-CoA dehydrogenase. Carboxymethylation of this residue may disrupt the precise orientation of the substrate required to achieve transfer of reducing equivalents to the flavin. Pig kidney general acyl-CoA dehydrogenase does not contain exposed catalytically essential cysteine residues.
mesh_terms: D044944:Acyl-CoA Dehydrogenases / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D007461:Iodoacetates / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D046911:Macromolecular Substances; D008715:Methionine / Q000032:analysis*; D010171:Palmitoyl Coenzyme A; D011485:Protein Binding; D013053:Spectrophotometry; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013552:Swine
chemical_list: D000596:Amino Acids; D007461:Iodoacetates; D046911:Macromolecular Substances; D013439:Sulfhydryl Reagents; D010171:Palmitoyl Coenzyme A; D008715:Methionine; D044944:Acyl-CoA Dehydrogenases