Biomaterial Database

Effect of nicotinamide adenine dinucleotide on the oxidation-reduction potentials of lipoamide dehydrogenase from pig heart. 1984

K Maeda-Yorita, and K Aki

The effect of NAD+ on lipoamide dehydrogenase from pig heart was investigated physicochemically. The observed and theoretical oxidation-reduction mid-point potentials for the oxidized lipoamide dehydrogenase (E)/two-electron-reduced lipoamide dehydrogenase (EH2) couple in the presence on NAD+ were -218 mV and -251 mV, respectively, at pH 6.0. Therefore, unexpectedly the mid-point potential of the enzyme became more positive on NAD+ binding. Decreases in the fluorescence lifetime and intensity and increase in the degree of polarization of enzyme-bound FAD were observed in the presence of NAD+. Fluorescence quenching of bound FAD by NAD+ was released by phenobarbital. The results suggest that NAD+ strengthens the intramolecular dynamic interaction between the isoalloxazine moiety and adenine moiety of bound FAD, and so alters the mid-point potential of the enzyme. These findings indicate that NAD+ acts not only as an acceptor of electrons from EH2, but also as an effector in the flavin-disulfide interaction of EH2.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008058	Dihydrolipoamide Dehydrogenase	A flavoprotein containing oxidoreductase that catalyzes the reduction of lipoamide by NADH to yield dihydrolipoamide and NAD+. The enzyme is a component of several MULTIENZYME COMPLEXES.	Lipoamide Dehydrogenase,NAD Diaphorase,NADH Diaphorase,Diaphorase (Lipoamide Dehydrogenase),Dihydrolipoyl Dehydrogenase,Glycine Decarboxylase Complex L-Protein,L-Protein, Glycine Decarboxylase Complex,Lipoamide Dehydrogenase, Valine,Lipoic Acid Dehydrogenase,Lipoyl Dehydrogenase,Valine Lipoamide Dehydrogenase,Dehydrogenase, Dihydrolipoamide,Dehydrogenase, Dihydrolipoyl,Dehydrogenase, Lipoamide,Dehydrogenase, Lipoic Acid,Dehydrogenase, Lipoyl,Dehydrogenase, Valine Lipoamide,Diaphorase, NAD,Diaphorase, NADH,Glycine Decarboxylase Complex L Protein
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D009243	NAD	A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)	Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D011199	Potentiometry	Solution titration in which the end point is read from the electrode-potential variations with the concentrations of potential determining ions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic