title: Essential role of coenzyme A in pyruvate dehydrogenase kinase activity.
abstract: The rate of phosphorylation and concomitant inactivation of purified pig heart muscle pyruvate dehydrogenase complex by intrinsic kinase (EC 2.7.1.99) is markedly accelerated by the addition of coenzyme A to the incubation medium, showing a half-maximum effect at 1.8 microM. The pantetheine moiety is the effective part of the coenzyme A molecule. The free thiol group is prerequisite for the stimulatory action, acetyl-CoA, benzoyl-CoA or CoAS-SCoA being ineffectual. The thiol's specificity is evidenced by showing that dithiothreitol, 2-mercaptoethanol or glutathione up to 5 mM failed to replace coenzyme A. The possibility is considered that coenzyme A might act as a physiological modifier of pyruvate dehydrogenase kinase activity.
mesh_terms: D000818:Animals; D003065:Coenzyme A / Q000494:pharmacology*; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D013552:Swine
chemical_list: D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D013438:Sulfhydryl Compounds; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D003065:Coenzyme A