Nitrite reductase activity

To provide a model for nitrite reductases72 Karlin and co-workers characterized a nitrite-bound complex (226) (r = 0.05)214 In an endeavor to model nitrite reductase activity, Tanaka and co-workers prepared a few mononuclear complexes (227) (r = 0.74)215 (228) (r = 0.82),216 (229) (r = 0.97),217 (230) (r = 0.16),217 (231) (r = 0.07),217 and (232) (r = 0.43 and r = 0.53)217 and studied the electrochemical reduction of N02A As a part of their activity on modeling heme-copper terminal oxidases, Holm and co-workers prepared complex (233) (r = 0.96).218 Using a sterically hindered tris(pyridylmethyl)amine, Canary et al. prepared a complex (234) (r=1.00), studied its redox behavior, and discussed various factors that may contribute to the difference (higher potential for the new complex) in the redox potential of a Cu Cu1 couple between substituted and unsubstituted ligands.2 9... 

Zhang, Z., Naughton, D., Winyard, P. G., Benjamin, N., Blake, D. R., Symons, M. C. R., Generation of nitric oxide by a nitrite reductase activity of xanthine oxidase a potential pathway for nitric oxide formation in the absence of nitric oxide synthase activity. Biochem. Biophys. Res. Commun. 249 (1998), p. 767—772... 

These include nitrite and trimethylammonium oxide. Nitrite undergoes a six-electron reduction to give ammonia in a reaction catalyzed by a nitrite reductase. Nitrite reductase activity with lactate and formate has been reported, although other donors may support the reduction of nitrite. It should be noted that at least three pathways in E. coli exist for the reduction of nitrite. 

Sharma, A.K. Sopory, S.K. (1984) Independent effects of phytochrome and nitrate on nitrate reductase and nitrite reductase activities in maize. Photochemistry and Photobiology 39, 491-3. 

Yamanaka and co-workers (364-366) have crystallized a cytochrome oxidase from P. aeruginosa which oxidizes Pseudomonas ferrocytochrome c-551. It is also capable of nitrite reduction with a turnover number of 4000 moles nitrite reduced under anaerobic conditions to nitric oxide per minute at 37°. It is an adaptive enzyme, nitrate being essential for its biosynthesis. The enzyme has a molecular weight of 120,000, with two subunits of equivalent molecular weight, 2 heme c and 2 heme d groups per mole (Fig. 38) (366a). Nitrite reductase activity is 94% inhibited by 8 X 10 M KCN, but only by CO. The lack of CO inhibition appears to be related to the fact that the enzyme has a greater affinity for nitrite than for carbon monoxide. 

Suzuki, 1., Sugiyama, T., and Omata, T. (1995). Regulation of nitrite reductase activity imder CO2 limitation in the cyanobacterium Synechococcus sp. PCC 7942. Plant Physiol. 107, 791—796. 

Since nitrite reductase activity is impaired, however, the cells then excrete much of the excess accumulated back to the water. Iron/hght co-limitation of... 

Fig. 11 Effect of specific inhibitors of the respiratory chain on the nitrite reductase activity of rat liver mitochondria. Mitochondria were incubated with nitrite for 2 h under argon in the presence of succinate or glutamate/malate (Glu/Mal). Nitric monoxide derived from nitrite was trapped with hemoglobin. The concentration of NO-hemoglobin complexes was measured using low temperature ESR spectroscopy. Other details are described in Kozlov et al. [46]. CON control, ROT rotenone, TTFA thenoyltrifluoroacetone, MYX myxothiazol, AA antimycin A...

Yamanaka T, Okunuki K (1963b) Crystalline Pseudomonas cytochrome oxidase II. Spectral properties of the enzyme. Biochim Biophys Acta 67 394-406 Yamanaka T, Okunuki K (1963c) Crystalline Pseudomonas cytochrome oxidase III. Properties of the prosthetic groups. Biochim Biophys Acta 67 407-416 Yamanaka T, Ota A, Okunuki K (1960) Nitrite reductase activity of Pseudomonas cytochrome oxidase. Biochim Biophys Acta 44 397-398... 

Nitrogen-fixing plants are also capable of reducing NOg" in the roots and/or leaves of the plant. In soybeans, there is evidence to suggest that reduction may occur in both roots and leaves (26). There has been diflSculty, however, in detecting nitrite reductase activity in soybean root or nodule tissue (61). Using NOs", we have demonstrated that both tissues actively assimilate and incorporate into organic com-... 

In 1%7, Miflin reported that a particulate fraction from pea or barley roots was able to reduce nitrite using reduced benzyl viologen as the electron donor. Miflin (1970) and Bourne and Miflin (1970) isolated a barley root particle that reduced nitrate to ammonia when provided with pyruvate and ATP. The fractionation techniques used separated the nitrosome from the mitochondrial and peroxisomal fractions. Dalling et al. (1972b) found that 15% of the total nitrite reductase activity of wheat roots was associated with an organelle that was tentatively identified as a proplastid. A proplastid location for nitrite reductase in tissue culture cells has been indicated by Washitani and Sato (1977a,b). 

In nitrite-ammonifying bacteria, especially in enterobacteria, there may exist two independently regulated dissimilatory ways of nitrite reduction to ammonia with two different physiological functions [125]. A cytoplasmic siroheme-dependent nitrite reductase activity (NADH nitrite oxidoreductase) [138,139] confers on... 

Xanthine oxidase can reduce nitrate to nitrite (Westerfield et al. 1959, Fridovich and Handler 1962). Xanthine oxidase and dissimilatory nitrate reductase share structural similarities. Both are molybdoenzymes and contain flavin adenine dinucleotide and Fe/S clusters (McCord 1985, Mitchell 1986, Payne et al. 1997). Zhang et al. (1998) reported that both purified bovine buttermilk xanthine oxidase and xanthine oxidase-containing inflamed human synovial tissue can generate NO by reducing nitrite in the presence of NADH. This nitrite reductase activity of xanthine oxidase may act as a supplement to the activity of nitric oxide synthase (NOS) to redistribute blood flow to ischaemic tissues when NOS activity is absent. 

Hsu SCN, Chang YL, Chuang W-J, et al. Copper(I) nitro complex with an anionic [HB(3,5-Me2Pz)3] ligand a synthetic model for the copper nitrite reductase active site. Inorg Chem. 2012 51 9297-9308. 

Roche, C.J., Dantsker, D., Samuni, U., and Friedman, J.M. (2006) Nitrite reductase activity of sol-gel-encapsulated deoxyhemoglobin influence of quaternary and tertiary structure./. Biol. Chem.,... 

Lui, EE. and Kluger, R, Enhancing nitrite reductase activity of modified hemoglobin Bis-tetramers and their PEGylated derivatives. Biochemistry 48 11912-11919,2009. 

Nitrite reductase is regulated by nitrate and light in a manner similar to NR. Nitrite reductase activity increases in response to nitrate or nitrite (Ingle et al. 

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