Long-term regulation of pyruvate dehydrogenase complex. Evidence that kinase-activator protein (KAP) is free pyruvate dehydrogenase kinase.
The kinase-activator protein (KAP) of pyruvate dehydrogenase complex (PDC) has been purified approx. 2250-fold from high-speed supernatants of mitochondrial extracts from the liver of 48 h-starved rats. Purified KAP demonstrates kinase activity towards both the E1 component of PDC and towards a synthetic peptide corresponding to the major phosphorylation site on E1. Furthermore, the activities of KAP and PDC kinase co-fractionate through several stages of purification and have the same apparent mass. We conclude that KAP is not a distinct protein, but is kinase which has dissociated from the complex.
Jones
B S
BS
Department of Biochemistry and Genetics, Medical School, University of Newcastle upon Tyne, U.K.
Yeaman
S J
SJ
D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D008930:Mitochondria, Liver / Q000201:enzymology; D008970:Molecular Weight; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex / Q000302:isolation & purification / Q000378:metabolism*; D013217:Starvation / Q000201:enzymology
D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases