Biomaterial Database

[Diaphorase reactions of lipoamide dehydrogenases from the adrenal ketoglutarate dehydrogenase complex]. 1985

N K Chenas, and A A Butkus, and Iu Iu Kulis

Lipoamide dehydrogenase, a component of the bovine adrenal ketoglutarate dehydrogenase complex, catalyzes the oxidation of NADH by p-quinones and ferricyanide. The kinetics of oxidation obey the ping-pong mechanism. At pH 7.0, the constants for the active center oxidation by quinones (kox) are equal to 1.1 X 10(4)-5.3 X 10(5) M-1s-1 and increase as the acceptor potential rises. The values of kox for quinones change insignificantly within the pH range of 7.7-5.0, whereas that for ferricyanide increases 10-fold with a decrease of pH from 7.0 to 5.0. The value of the catalytic constant for the enzyme (kcat) reaches its maximum at pH 5.5. The quinones interact with the thiol groups of lipoamide dehydrogenase by inhibiting the fluorescence of FAD and diaphorease activity. The reaction is catalyzed by a basic amino acid (pK 6.7) within the composition of the enzyme.

UI	MeSH Term	Description	Entries
D007655	Ketoglutarate Dehydrogenase Complex		2-Keto-4-Hydroxyglutarate Dehydrogenase,2-Oxoglutarate Dehydrogenase,2-Oxoglutarate Dehydrogenase Complex,Oxoglutarate Dehydrogenase,alpha-Ketoglutarate Dehydrogenase,alpha-Ketoglutarate Dehydrogenase Complex,2 Keto 4 Hydroxyglutarate Dehydrogenase,2 Oxoglutarate Dehydrogenase,2 Oxoglutarate Dehydrogenase Complex,Complex, 2-Oxoglutarate Dehydrogenase,Complex, Ketoglutarate Dehydrogenase,Complex, alpha-Ketoglutarate Dehydrogenase,Dehydrogenase Complex, 2-Oxoglutarate,Dehydrogenase Complex, Ketoglutarate,Dehydrogenase Complex, alpha-Ketoglutarate,Dehydrogenase, 2-Keto-4-Hydroxyglutarate,Dehydrogenase, 2-Oxoglutarate,Dehydrogenase, Oxoglutarate,Dehydrogenase, alpha-Ketoglutarate,alpha Ketoglutarate Dehydrogenase,alpha Ketoglutarate Dehydrogenase Complex
D007658	Ketone Oxidoreductases	Oxidoreductases that are specific for KETONES.	Oxidoreductases, Ketone
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
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
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
D011809	Quinones	Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D005182	Flavin-Adenine Dinucleotide	A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)	FAD,Flavitan,Dinucleotide, Flavin-Adenine,Flavin Adenine Dinucleotide