Flavin-Containing Enzyme, Nitrate Reductase, Ankistrodesmus braunii Ankistrodesmus braunii NAD(P)H-nitrate reductase is a complex hemoflavomolybdoprotein composed by eight similar subunits. The flavin prosthetic group, identified as FAD, is essential for the NAD(P)H-dependent activities of the complex, and is located before the heme chromophore in the enzyme electron transport chain from reduce...

A nitrate reductase (EC 1.6.6.1)-inactivating factor has been isolated from 8-day-old wheat leaves. The purification schedule involved ammonium sulfate precipitation, Sephadex G-100 filtration, DEAE-cellulose chromatography, and Sephadex G-150 filtration. No accurate assessment could be made as to the degree of purification relative to crude extract as the inactivating factor could not be detec...

The effect of various day temperatures on NADH-nitrate reductase, NADH- and NADPH-glutamate dehydrogenases, nitrate, protein and leaf area, measured at intervals during the ontogeny of the first trifoliolate soybean leaf, was determined. At 32.5 C and 25 C, nitrate concentration, nitrate reductase, and NADPH-glutamate dehydrogenase activities increased concurrently with leaf development and the...

After x-ray irradiation, 13 mutants of Chlorella sorokiniana incapable of using NO(3) (-) as N source were isolated using a pinpoint method. Using immunoprecipitation and Western blot assays, no nitrate reductase was found in five strains while in eight mutants the enzyme was detected. The latter strains contained different patterns of nitrate reductase partial reactions. All isolates were of t...

aerogenes was investigated. The only quinone found in measurable amounts in bacteria grown in minimal media under both aerobic and anaerobic conditions was ubiquinone-8. Membrane-bound ubiquinone-8 could be removed by extraction with pentane, or destroyed by ultraviolet irradiation, with a concomitant loss of both reduced nicotinamide adenine dinucleotide (NADH) oxidase and NADH-linked respirat...

The specific activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase were determined in intact protoplasts and intact chloroplasts from Chlamydomonas reinhardtii. After correction for contamination, the data were used to calculate the portion of each enzyme in the algal chloroplast. The chloroplast of C. reinhardtii contained all...

Background: To study methaemoglobin content and NADH-methaemoglobin reductase activity of three human erythrocyte genotypes (HbAA, HbAS and HbSS).Materials and Methods: Studies to ascertain methaemoglobin concentration and level of NADH-methaemoglobin reductase activity of three human erythrocyte genotypes (HbAA, HbAS and HbSS) were carried out in forty-three (43) healthy male participants of c...

Inorganic orthophosphate (25 millimolar in assay media; Pi) was found to increase in vitro activity of NADH-nitrate reductase (NR) isolated from 2-row barley (Hordeum vulgare L.) leaves with a saturating concentration of nitrate (2 millimolar) but to decrease it with low nitrate levels (<0.1 millimolar). The response to nitrate concentrations was Pi specific. The Lineweaver-Burk plot showed tha...

The nitrate reductase in the mature root extract of 3-day maize (Zea mays) seedlings was relatively labile in vitro. Insoluble polyvinylpyrrolidone used in the extraction medium produced only a slight increase in the stability of the enzyme. Mixing the mature root extract with that of the root tip promoted the inactivation of nitrate reductase in the latter. The inactivating factor in the matur...