title: Sites of phosphorylation on pyruvate dehydrogenase from bovine kidney and heart.
abstract: The highly purfied pyruvate dehydrogenase complex (EC 1.2.4.1) and uncomplexed pyruvate dehydrogenase from bovine kidney and heart mitochondria were phosphorylated and inactivated with pyruvate dehydrogenase kinase and [gamma-32P]ATP. Tryptic digestion of the phosphorylated pyruvate dehydrogenase yielded three phosphopeptides, a mono- (site 1) and a di- (sites 1 and 2) phosphorylated tetradecapeptide and a monophosphorylated nonapeptide (site 3). The amino acid sequences of the three phosphopeptides were established to be Tyr-His-Gly-His-Ser(P)-Met-Ser-Asn-Pro-Gly-Val-Ser-Tyr-Arg, Tyr-His-Gly-His-Ser(P)-Met-Ser-Asn-Pro-Gly-Val-Ser(P)-Tyr-Arg, and Tyr-Gly-Met-Gly-Thr-Ser(P)-Val-Glu-Arg. Phosphorylation proceeded markedly faster at site 1 than at sites 2 and 3, and phosphorylation at site 1 correlated closely with inactivation of pyruvate dehydrogenase. Complete inactivation of pyruvate dehydrogenase was associated with incorporation at site 1 of 1.0--1.6 mol of phosphoryl groups per mol of enzyme. Since pyruvate dehydrogenase is a tetramer (alpha2beta2) and since phosphorylation occurs only on the alpha subunit, the possibility of half-site reactivity is considered.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D007668:Kidney / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D010748:Phosphopeptides / Q000302:isolation & purification; D010750:Phosphoproteins / Q000378:metabolism*; D011487:Protein Conformation; D011768:Pyruvate Dehydrogenase Complex / Q000037:antagonists & inhibitors*; D012694:Serine; D014357:Trypsin
chemical_list: D010748:Phosphopeptides; D010750:Phosphoproteins; D011768:Pyruvate Dehydrogenase Complex; D012694:Serine; D000255:Adenosine Triphosphate; D014357:Trypsin