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

Yersinia was investigated in 50 skin samples of chicken carcasses from retail shops and 65 samples of balanced food for domestic fowl. Enrichments were performed in saline phosphate buffer 0.067 M, pH 7.6 and post-enriched in 0.5% KOH. Subcultures were performed in Salmonella-Shigella agar and MacConkey agar. Isolates were identified through biochemical, serological and lysotyping methods. The following biovar (B), serovar (O) and phagovar (Lis) were isolated from chickens: Y. enterocolitica (five strains) B:1:O:6,47;Lis Xz; B:1;O:6:Lis Xz; B:1:O:5,Lis Xz; Y.intermedia (two strains) B:1;O:52;Lis Xz; B:1;O:52,53,54;Lis Xz (NRA, nitrate reductase type A); Y. frederiksenii (two strains) O:10,K1,25,35,38,46:Lis Xz; (citrate): O:10,K1,25,35,38,46:Lis Xz (ONPG-: citrate +); Y. kristensenii (one strain) does not agglutinate; Lis Xo. Yersinia were not isolated from balanced food for domestic fowl. Virulence tests (calcium dependency and autoagglutination at 37 degrees C) were negative in all instances. It is concluded from this study that Yersinia isolated from chickens are without pathogenic importance.
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PMID:[Bacteria of the genus Yersinia in chickens for human consumption and in balanced bird food]. 181 65

Assimilatory nitrate reductase [NAD(P)H] (EC 1.6.6.2) from Ankistrodesmus braunii has been purified to homogeneity by a simple procedure that utilizes as the main step affinity chromatography on Blue-Sepharose. The best enzyme preparation has a specific activity of 61.25 units/mg protein. The enzyme has a sedimentation coefficient of 10.9 S by sucrose-density-gradient centrifugation, and a Stokes radius of 9.8 nm was estimated by gel filtration techniques. Its molecular weight is 460000, but only one single band of 58000 was detected after sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The native enzyme seems thus to be composed of eight subunits. The nitrate reductase absorption spectrum shows wavelengths maxima at 280 and 416 nm and a broad shoulder at 450 nm. Reduced enzyme shows maxima at 424 (Soret), 527 (beta) and 557 (alpha) nm, and a bleaching at 450 nm. The reduced extracted heme chromophore, in pyridine and KOH, shows absorption bands at 414, 522 and 552 nm. These properties indicate the presence of a b-type cytochrome and flavin as prosthetic groups of A. braunii nitrate reductase. A minimum of four molecules of heme has been calculated per molecule of the enzyme complex. Redox titration of the enzyme shows a midpoint potential for the heme of -73 mV at pH 7.0. In the presence of p-hydroxymercuribenzoate, which inhibits the NAD(P)H-dependent activities of the complex, the enzyme-bound heme can be reduced with dithionite, but not with NAD(P)H.
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PMID:Purification and properties of assimilatory nitrate reductase [NAD(P)H] from Ankistrodesmus braunii. 720 Apr 26

We have used two hydroxylated naphthoquinol menaquinol analogues, reduced plumbagin (PBH2, 5-hydroxy-2-methyl-1,4-naphthoquinol) and reduced lapachol [LPCH2, 2-hydroxy-3-(3-methyl-2-butenyl)-1, 4-naphthoquinol], as substrates for Escherichia coli anaerobic reductases. These compounds have optical, solubility and redox properties that make them suitable for use in studies of the enzymology of menaquinol oxidation. Oxidized plumbagin and oxidized lapachol have well resolved absorbances at 419 nm (epsilon=3.95 mM-1. cm-1) and 481 nm (epsilon=2.66 mM-1.cm-1) respectively (in Mops/KOH buffer, pH 7.0). PBH2 is a good substrate for nitrate reductase A (Km=282+/-28 microM, kcat=120+/-6 s-1) and fumarate reductase (Km=155+/-24 microM, kcat=30+/-2 s-1), but not for DMSO reductase. LPCH2 is a good substrate for nitrate reductase A (Km=57+/-35 microM, kcat=68+/-13 s-1), fumarate reductase (Km=85+/-27 microM, kcat=74+/-6 s-1) and DMSO reductase (Km=238+/-30 microM, kcat=191+/-21 s-1). The sensitivity of enzymic LPCH2 and PBH2 oxidation to 2-n-heptyl-4-hydroxyquinoline N-oxide inhibition is consistent with their oxidation occurring at sites of physiological quinol binding.
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PMID:Hydroxylated naphthoquinones as substrates for Escherichia coli anaerobic reductases. 957 48