Characteristics of nitrite reductase activity in Lactobacillus lactis TS4

Nitrite reductase activity in Lactobacillus lactis TS4 was induced by the presence of nitrite and was active under anaerobic conditions. An electron donor was required. Glucose was the most efficient donor in whole cells, while NADH was the most efficient in cell extracts. The optimum nitrite concentration for reduction was 2.0 mM, with higher levels sharply inhibiting activity. The pH optimum for nitrite reduction by resting cell suspensions was 7.2, and the temperature optimum was 30 °C. High levels of NADH oxidase activity in cell extracts interfered with nitrite reductase activity. Fractionation of the cell extract by ultracentrifugation and ammonium sulphate precipitation decreased the specific activity of NADH oxidase by 40 and 41%, respectively. Nitrite reductase activity was detected in the supernatant fluid after centrifugation of cell extract at 226 000 × g for 1 h.

Download Full-text

Identification of the sources of nitrous oxide produced by oxidative and reductive processes in Nitrosomonas europaea

Biochemical Journal ◽

10.1042/bj1261181 ◽

1972 ◽

Vol 126 (5) ◽

pp. 1181-1191 ◽

Cited By ~ 186

Author(s):

G. A. F. Ritchie ◽

D. J. D. Nicholas

Keyword(s):

Nitrite Reductase ◽

Ammonia Oxidation ◽

Reductase Activity ◽

Close Association ◽

Nitrosomonas Europaea ◽

Nitrite Reduction ◽

Anaerobic Conditions ◽

Cell Extracts ◽

Artificial Electron Acceptor ◽

Nitrite Reductase Activity

1. Cells of Nitrosomonas europaea produced N2O during the oxidation of ammonia and hydroxylamine. 2. The end-product of ammonia oxidation, nitrite, was the predominant source of N2O in cells. 3. Cells also produced N2O, but not N2 gas, by the reduction of nitrite under anaerobic conditions. 4. Hydroxylamine was oxidized by cell-free extracts to yield nitrite and N2O aerobically, but to yield N2O and NO anaerobically. 5. Cell extracts reduced nitrite both aerobically and anaerobically to NO and N2O with hydroxylamine as an electron donor. 6. The relative amounts of NO and N2O produced during hydroxylamine oxidation and/or nitrite reduction are dependent on the type of artificial electron acceptor utilized. 7. Partially purified hydroxylamine oxidase retained nitrite reductase activity but cytochrome oxidase was absent. 8. There is a close association of hydroxylamine oxidase and nitrite reductase activities in purified preparations.

Download Full-text

Increased nitrite reductase activity of fetal versus adult ovine hemoglobin

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00601.2008 ◽

2009 ◽

Vol 296 (2) ◽

pp. H237-H246 ◽

Cited By ~ 21

Author(s):

Arlin B. Blood ◽

Mauro Tiso ◽

Shilpa T. Verma ◽

Jennifer Lo ◽

Mahesh S. Joshi ◽

...

Keyword(s):

Nitrite Reductase ◽

Chronic Hypoxia ◽

Reductase Activity ◽

Fetal Hemoglobin ◽

Nitrite Reduction ◽

No Production ◽

Low Oxygen ◽

Nitrite Reductase Activity ◽

Adult Hemoglobin ◽

Severe Ischemia

Growing evidence indicates that nitrite, NO2−, serves as a circulating reservoir of nitric oxide (NO) bioactivity that is activated during physiological and pathological hypoxia. One of the intravascular mechanisms for nitrite conversion to NO is a chemical nitrite reductase activity of deoxyhemoglobin. The rate of NO production from this reaction is increased when hemoglobin is in the R conformation. Because the mammalian fetus exists in a low-oxygen environment compared with the adult and is exposed to episodes of severe ischemia during the normal birthing process, and because fetal hemoglobin assumes the R conformation more readily than adult hemoglobin, we hypothesized that nitrite reduction to NO may be enhanced in the fetal circulation. We found that the reaction was faster for fetal than maternal hemoglobin or blood and that the reactions were fastest at 50–80% oxygen saturation, consistent with an R-state catalysis that is predominant for fetal hemoglobin. Nitrite concentrations were similar in blood taken from chronically instrumented normoxic ewes and their fetuses but were elevated in response to chronic hypoxia. The findings suggest an augmented nitrite reductase activity of fetal hemoglobin and that the production of nitrite may participate in the regulation of vascular NO homeostasis in the fetus.

Download Full-text

The functional nitrite reductase activity of the heme-globins

Blood ◽

10.1182/blood-2008-01-115261 ◽

2008 ◽

Vol 112 (7) ◽

pp. 2636-2647 ◽

Cited By ~ 184

Author(s):

Mark T. Gladwin ◽

Daniel B. Kim-Shapiro

Keyword(s):

Small Molecules ◽

Nitrite Reductase ◽

Reductase Activity ◽

Vital Role ◽

Nitrite Reduction ◽

Cellular Respiration ◽

Oxygen Binding ◽

Nitrite Reductase Activity ◽

Hypoxic Vasodilation ◽

Anaerobic Conversion

AbstractHemoglobin and myoglobin are among the most extensively studied proteins, and nitrite is one of the most studied small molecules. Recently, multiple physiologic studies have surprisingly revealed that nitrite represents a biologic reservoir of NO that can regulate hypoxic vasodilation, cellular respiration, and signaling. These studies suggest a vital role for deoxyhemoglobin- and deoxymyoglobin-dependent nitrite reduction. Biophysical and chemical analysis of the nitrite-deoxyhemoglobin reaction has revealed unexpected chemistries between nitrite and deoxyhemoglobin that may contribute to and facilitate hypoxic NO generation and signaling. The first is that hemoglobin is an allosterically regulated nitrite reductase, such that oxygen binding increases the rate of nitrite conversion to NO, a process termed R-state catalysis. The second chemical property is oxidative denitrosylation, a process by which the NO formed in the deoxyhemoglobin-nitrite reaction that binds to other deoxyhemes can be released due to heme oxidation, releasing free NO. Third, the reaction undergoes a nitrite reductase/anhydrase redox cycle that catalyzes the anaerobic conversion of 2 molecules of nitrite into dinitrogen trioxide (N2O3), an uncharged molecule that may be exported from the erythrocyte. We will review these reactions in the biologic framework of hypoxic signaling in blood and the heart.

Download Full-text

Ammonification in Bacillus subtilisUtilizing Dissimilatory Nitrite Reductase Is Dependent onresDE

Journal of Bacteriology ◽

10.1128/jb.180.1.186-189.1998 ◽

1998 ◽

Vol 180 (1) ◽

pp. 186-189 ◽

Cited By ~ 55

Author(s):

Tamara Hoffmann ◽

Nicole Frankenberg ◽

Marco Marino ◽

Dieter Jahn

Keyword(s):

Electron Acceptor ◽

Nitrite Reductase ◽

Reductase Activity ◽

Regulatory System ◽

Nitrate Respiration ◽

Benzyl Viologen ◽

Cell Extracts ◽

Negative Effect ◽

Nitrite Reductase Activity ◽

Dissimilatory Nitrite Reductase

ABSTRACT During anaerobic nitrate respiration Bacillus subtilisreduces nitrate via nitrite to ammonia. No denitrification products were observed. B. subtilis wild-type cells and a nitrate reductase mutant grew anaerobically with nitrite as an electron acceptor. Oxygen-sensitive dissimilatory nitrite reductase activity was demonstrated in cell extracts prepared from both strains with benzyl viologen as an electron donor and nitrite as an electron acceptor. The anaerobic expression of the discovered nitrite reductase activity was dependent on the regulatory system encoded by resDE. Mutation of the gene encoding the regulatory Fnr had no negative effect on dissimilatory nitrite reductase formation.

Download Full-text

Erratum: Characteristics of nitrite reductase activity in Lactobacillus lactis TS4

Canadian Journal of Microbiology ◽

10.1139/m85-182 ◽

1985 ◽

Vol 31 (10) ◽

pp. 964-964

Author(s):

Karen L. Dodds ◽

David L. Collins-Thompson

Keyword(s):

Nitrite Reductase ◽

Reductase Activity ◽

Nitrite Reductase Activity ◽

Lactobacillus Lactis

Download Full-text

Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

Microbiology ◽

10.1099/mic.0.28524-0 ◽

2006 ◽

Vol 152 (5) ◽

pp. 1479-1488 ◽

Cited By ~ 5

Author(s):

William P. Laratta ◽

Michael J. Nanaszko ◽

James P. Shapleigh

Keyword(s):

Electron Transfer ◽

Electron Donor ◽

Rhodobacter Sphaeroides ◽

Nitrite Reductase ◽

Double Mutant ◽

Reductase Activity ◽

Nitrite Reduction ◽

Nitrite Reductase Gene ◽

Nitrite Reductase Activity

The role of cytochrome c 2, encoded by cycA, and cytochrome c Y, encoded by cycY, in electron transfer to the nitrite reductase of Rhodobacter sphaeroides 2.4.3 was investigated using both in vivo and in vitro approaches. Both cycA and cycY were isolated, sequenced and insertionally inactivated in strain 2.4.3. Deletion of either gene alone had no apparent effect on the ability of R. sphaeroides to reduce nitrite. In a cycA–cycY double mutant, nitrite reduction was largely inhibited. However, the expression of the nitrite reductase gene nirK from a heterologous promoter substantially restored nitrite reductase activity in the double mutant. Using purified protein, a turnover number of 5 s−1 was observed for the oxidation of cytochrome c 2 by nitrite reductase. In contrast, oxidation of c Y only resulted in a turnover of ∼0·1 s−1. The turnover experiments indicate that c 2 is a major electron donor to nitrite reductase but c Y is probably not. Taken together, these results suggest that there is likely an unidentified electron donor, in addition to c 2, that transfers electrons to nitrite reductase, and that the decreased nitrite reductase activity observed in the cycA–cycY double mutant probably results from a change in nirK expression.

Download Full-text

La dénitrification chez Bacillus licheniformis

Canadian Journal of Microbiology ◽

10.1139/m78-008 ◽

1978 ◽

Vol 24 (1) ◽

pp. 45-49 ◽

Cited By ~ 12

Author(s):

F. Pichinoty ◽

J.-L. Garcia ◽

C. Job ◽

M. Durand

Keyword(s):

Nitric Oxide ◽

Gas Chromatography ◽

Nitrate Reductase ◽

Electron Donor ◽

Bacillus Licheniformis ◽

Nitrite Reductase ◽

Reductase Activity ◽

Cell Extracts ◽

Nitrite Reductase Activity ◽

Peptone Medium

The denitrifying capacity of 15 strains of Bacillus licheniformis was evaluated. In general, N2 production by the cultures on complex media containing NO3− is irregular and quite slow and three of the strains never produce gas. Bacillus licheniformis grows rapidly in anaerobiosis on peptone medium containing NO3− which is reduced to NO2−. None of the strains grow in peptone medium with NO2− or N2O as the respiratory substrate, nor do they grow under an atmosphere of 10% NO–90% N2. Denitrification was studied in cell suspensions using gas chromatography. N2O production from NO3− or NO2− is always weak at best; nitric oxide is reduced to N2O at an appreciable rate. All the strains synthesize nitrate reductase A in anaerobiosis when NO3− is present. In cell extracts, nitrite reductase activity is always negligible or nil with tetramethyl-p-phenylenediamine as an electron donor.

Download Full-text