title: Dephosphorylation and reactivation of phosphorylated purified ox-kidney branched-chain dehydrogenase complex by co-purified phosphatase.
abstract: The branched-chain 2 oxoacid dehydrogenase complex has been purified from well-washed ox-kidney mitochondria together with branched-chain dehydrogenase kinase. The complex was inactivated and phosphorylated by ATP in about 5 min at 30 degrees C. After hydrolysis of ATP by a contaminating ATPase (5-10 min) the complex was dephosphorylated and reactivated. Dephosphorylation and reactivation were linearly correlated. Reactivation was dependent upon Mg2+ (K0.5 greater than 1 mM) and inhibited completely by 50 mM fluoride. Reactivation and dephosphorylation are attributed to a mitochondrial branched-chain dehydrogenase phosphatase.
mesh_terms: D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D004793:Enzyme Reactivators; D005459:Fluorides / Q000494:pharmacology; D007658:Ketone Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000494:pharmacology*; D010766:Phosphorylation
chemical_list: D004793:Enzyme Reactivators; D009097:Multienzyme Complexes; D007658:Ketone Oxidoreductases; D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D010744:Phosphoric Monoester Hydrolases; D008274:Magnesium; D005459:Fluorides; D002118:Calcium