Nitroreductase activity of heart lipoamide dehydrogenase
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چکیده
منابع مشابه
Nitroreductase activity of heart lipoamide dehydrogenase.
A novel reaction catalysed by lipoamide dehydrogenase is described. In the presence of NADH, lipoamide dehydrogenase reduces the nitro group of 4-nitropyridine and 4-nitropyridine N-oxide. The elution profiles from a DEAE-cellulose column for the dehydrogenase and nitroreductase activities are identical. Chemical modifications of critical amino acid residues suggest that the two activities shar...
متن کاملLipoamide dehydrogenase from human liver.
Lipoamide dehydrogenase (reduced nicotinamide adenine dinucleotide :lipoamide oxidoreductase, EC 1.6.4.3) has been isolated from acid-precipitated human liver particles in a highly purified state by a freezing and thawing technique instead of the heat treatment used by other workers. The enzyme was found to have a molecular weight of 138,000, and to contain 2 moles of flavin adenine dinucleotid...
متن کاملKinetics of Matrix-bound Lipoamide Dehydrogenase
Lipoamide dehydrogenase (EC 1.6.4.3) has been succesfully linked to a CNBr-activated polysaccharide matrix, Sepharose-4B, under different reaction conditions. The enzyme is probably bound more homogeneously at lower pH values (pH 7.5) than at pH 8.5. Such immobilized preparations yield V values 8 — 30% of the value of the V of the free enzyme (18,600 mole/min/mole of flavin). A low level of CNB...
متن کاملLipoamide dehydrogenase in serum: a preliminary report.
Lipoamide dehydrogenase was identified in serum and the optimal conditions for its assay at 30 degrees C were defined. The pH optimum in tris(hydroxymethyl)aminomethane buffer is 7.8, and activity is inhibited if buffer concentration exceeds 100 mmol/liter. Saturating concentrations of the substrates NAD+ and lipoamide are 3 mmol/liter and 5 mmol/liter, respectively. Activity is decreased eight...
متن کاملNADH inhibition and NAD activation of Escherichia coli lipoamide dehydrogenase catalyzing the NADH-lipoamide reaction.
A unique form of inhibition by NADH and partial reversal by NAD+ has been demonstrated with Escherichia coli lipoamide dehydrogenase. Substrate inhibition by NADH is consistent with its reduction of the active two-electron reduced enzyme intermediate to the inactive four-electron reduced form. NAD+ partially overcomes this inhibition by mass action reversal of this reduction. NAD+ activation is...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1987
ISSN: 0264-6021,1470-8728
DOI: 10.1042/bj2420447