Time-resolved fluorescence studies on NADH bound to mitochondrial malate dehydrogenase.
Time-resolved fluorescence studies on the emission of NADH bound to porcine heart mitochondrial malate dehydrogenase [S)-malate:NAD+ oxidoreductase, EC 1.1.1.37), in the presence and absence of saturating levels of hydroxymalonate, were carried out. The lifetime of NADH bound in the ternary complex was determined to be 9.5 ns compared to 1.74 ns as reported in the literature. Steady-state and dynamic polarization data indicated a Debye rotational relaxation time in the range of 106-109 ns for the dimeric enzyme. This value is significantly larger than that calculated for a spherical protein and is consistent with the asymmetric dimer found by crystallographic studies.
Jameson
D M
DM
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 73235.
Thomas
V
V
Zhou
D M
DM
D000818:Animals; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology; D009243:NAD / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013552:Swine
D009243:NAD; D008291:Malate Dehydrogenase