Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cibacron Blue F3GA, the chromophore of blue dextran, was tested at 4-16 mumol/l for possible inhibition of NADH dehydrogenase activity when added to mitochondrial preparations from cultured human skin fibroblasts. The free dye was shown to be a competitive inhibitor for NADH in the oxidation of NADH catalyzed by the mitochondrial enzyme. The Ki (5.8 mumol/l) for Cibacron Blue F3GA was considerably lower than the Michaelis constant (Km) found for NADH substrate (13.2-16.1 mumol/l), indicating a strong binding of the dye to the substrate-binding site of the enzyme. This is the first report of the competitive inhibition by Cibacron Blue F3GA of mitochondrial NADH in any species.
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PMID:Competitive inhibition of human mitochondrial NADH dehydrogenase by Cibacron Blue F3GA. 651 Apr 5

A ferricyanide-utilizing NADH dehydrogenase (NADH-ferricyanide oxidoreductase) from the plasma membrane of Ehrlich ascites tumour cells has been purified about 1500-fold to apparent homogeneity. The method comprises the isolation of an enriched plasma membrane fraction, solubilization with Triton X-100, ion-exchange chromatography, ammonium sulphate precipitation, Cibacron Blue chromatography and fast-protein liquid chromatography with a Superose-6 gel filtration column. The specific activity of the final pool was more than 61 units/mg protein. The pure enzyme examined by SDS/PAGE displayed only one type of subunit with an apparent molecular mass of 32.0 kDa. The molecular mass of the native protein (117.0 kDa) was estimated by gel filtration; these results suggest a protein composed of four subunits of identical molecular mass. The enzyme was stable in the pH interval between 6 and 9, with maximum activity at pH values from 7.5 to 8.5. The purified enzyme showed Michaelis-Menten kinetics for the substrates, with apparent K(m) values of 4.3 X 10(-5) M and 6.7 X 10(-5) M for NADH and ferricyanide respectively. The isolated protein was strongly inhibited by Zn2+ and the thio-specific reagents mersalyl and p-chloromercuribenzenesulphonic acid.
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PMID:Purification and characterization of a plasma membrane ferricyanide-utilizing NADH dehydrogenase from Ehrlich tumour cells. 867 74