title: Purification and properties of the Ascaris pyruvate dehydrogenase complex.
abstract: The pyruvate dehyhdrogenase complex (pyruvate:lipoate oxidoreductase (decarboxylating and acceptor-acetylating), EC 1.2.4.1) has been isolated from Ascaris muscle mitochondria and purified to near homogeneity by differential centrifugation, (NH4)2SO4 fractionation and calcium phosphate gel-cellulose chromatography. It is similar in shape, size and physical characteristics to pyruvate dehydrogenase complexes isolated from mammalian sources. It has an absolute dependence on CoA, NAD+ and pyruvate for activity and is competitively inhibited by acetyl-CoA and NADH. However, much higher NADH/NAD+ ratios are necessary to inhibit activity, suggesting regulation by the more reduced state of the pyridine nucleotide pool in Ascaris mitochondria.
mesh_terms: D000105:Acetyl Coenzyme A / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001200:Ascaris / Q000201:enzymology*; D001667:Binding, Competitive; D003065:Coenzyme A / Q000378:metabolism; D007700:Kinetics; D008931:Mitochondria, Muscle / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D011768:Pyruvate Dehydrogenase Complex / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D011773:Pyruvates / Q000378:metabolism
chemical_list: D011768:Pyruvate Dehydrogenase Complex; D011773:Pyruvates; D009243:NAD; D000105:Acetyl Coenzyme A; D000255:Adenosine Triphosphate; D003065:Coenzyme A