title: Kinetic characterization of the pyruvate and oxoglutarate dehydrogenase complexes from human heart.
abstract: The Michaelis constant values for the highly purified pyruvate dehydrogenase complex (PDC) from human heart are 25, 13 and 50 microM for pyruvate, CoA and NAD, respectively. Acetyl-CoA produces a competitive inhibition of PDC (Ki = 35 microM) with respect to CoA, whereas NADH produces the same type of inhibition with respect to NAD (Ki = 36 microM). The oxoglutarate dehydrogenase complex (OGDC) from human heart has active sites with two different affinities for 2-oxoglutarate ([S]0.5 of 30 and 120 microM). ADP (1 mM) decreases the [S]0.5 values by a half. The inhibition of OGDC (Ki = 81 microM) by succinyl-CoA is of a competitive type with respect to CoA (Km = 2.5 microM), whereas that of NADH (Ki = 25 microM) is of a mixed type with respect to NAD (Km = 170 microM).
authors.affiliation: Institute of Biochemistry, Byelorussian S. S. R. Academy of Sciences, Grodno, U. S. S. R.
authors.forename: Y V
authors.initials: YV
authors.lastname: Kiselevsky
authors.forename: S A
authors.initials: SA
authors.lastname: Ostrovtsova
authors.forename: S A
authors.initials: SA
authors.lastname: Strumilo
mesh_terms: D000328:Adult; D006801:Humans; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*
chemical_list: D011768:Pyruvate Dehydrogenase Complex; D007655:Ketoglutarate Dehydrogenase Complex