Hysteretic interaction of NADH and Mg2+ with mammalian NADH:CoQ reductase from beef heart.
Preincubation of submitochondrial particles (SMP) from beef heart in a reaction mixture containing low concentrations of Mg2+ induces a time lag in the NADH:oxidase activity. Preconditioning of the SMP by NADH, but not by NAD+, prevents the Mg2+-related time lag. The data obtained show that there exists a tight binding site for Mg2+ regulating the rate of electron transfer from NADH to the natural acceptor. The ability of Mg2+ to form a catalytically inactive complex with the enzyme is regulated by NADH.
Tushurashvili
P R
PR
Department of Biophysics, Tbilisi State University, USSR.
Dekanosidze
N Z
NZ
Inasaridze
N P
NP
Kekelidze
T N
TN
Tsartsidze
M A
MA
Lomsadze
B A
BA
D000818:Animals; D002417:Cattle; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000201:enzymology*; D008962:Models, Theoretical; D009243:NAD / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone); D010084:Oxidation-Reduction; D011808:Quinone Reductases / Q000378:metabolism*; D013367:Submitochondrial Particles / Q000201:enzymology*
D009243:NAD; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases; D008274:Magnesium