Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The plastoquinone antagonist 2,5-dibromothymoquinone was found to inhibit NO-3 reduction from NADH by the nitrate reductase complex from wheat. It accepts electrons from NADH through the NADH dehydrogenase activity of the nitrate reductase. However, it does not inhibit the reduction of 2,6-dichlorophenol-indophenol by the enzyme. This suggests that the two compounds may be accepting electrons at different places from the enzyme. Further it was observed that reduced DCIP could be oxidized by DBMIB in the absence of NADH indicating that the electron flow in the nitrate reductase complex may take place in a unidirectional way.
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PMID:Inhibition of the nitrate reductase complex by dibromothymoquinone. 15 94

The molybdenum iron-sulphur protein originally isolated from Desulfovibrio gigas by Moura, Xavier, Bruschi, Le Gall, Hall & Cammack [(1976) Biochem. Biophys. Res. Commun. 72, 782-789] has been further investigated by e.p.r. spectroscopy of molybdenum(V). The signal obtained on extended reduction of the protein with sodium dithionite has been shown, by studies at 9 and 35 HGz in 1H2O and 2H2O and computer simulations, to have parameters corresponding to those of the Slow signal from the inactive desulpho form of various molybdenum-containing hydroxylases. Another signal obtained on brief reduction of the protein with small amounts of dithionite was shown by e.p.r. difference techniques to be a Rapid type 2 signal, like that from the active form of such enzymes. In confirmation that the protein is a molybdenum-containing hydroxylase, activity measurements revealed that it had aldehyde:2,6-dichlorophenol-indophenol oxidoreductase activity. No such activity towards xanthine or purine was observed. Salicylaldehyde was a particularly good substrate, and treatment of the protein with it also gave rise to the Rapid signal. Molybdenum cofactor liberated from the protein was active in the nit-1 Neurospora crassa nitrate reductase assay. It is concluded that the protein is a form of an aldehyde oxidase or dehydrogenase. From the intensity of the e.p.r. signals and from enzyme activity measurements, 10-30% of the protein in the sample examined appeared to be in the functional form. The evolutionary significance of the protein, which may represent a primitive form of the enzyme rather than a degradation product, is discussed briefly.
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PMID:The molybdenum iron-sulphur protein from Desulfovibrio gigas as a form of aldehyde oxidase. 282 90