Kinetics of nitrite uptake and reduction by Chlamydomonas reinhardtii cells growing phototrophically has been studied by means of progress curves and the Michaelis-Menten integrated equation. Both uptake and reduction processes exhibited hyperbolic saturation kinetics, the nitrite uptake system lacking a diffusion component. Nitrite uptake and reduction showed significant differences in K(s) fo...

a new, simple, rapid, and cheap method for determination of trace amounts of nitrite ion is reported.determination is based on reduction of bromate ion by nitrite ion, in the presence of murexide inacidic media. during reaction of bromate ion with nitrite ion, the reaction mixture is decolorized.the absorbance changes is then monitored spectrophotometricaly at 520 nm, at 25 °c. dynamicrange of ...

Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characte...

Steady state rates of NADP reduction decline upon commencement of nitrite reduction in reconstituted chloroplast preparations. Similarly, steady state rates of nitrite reduction are lower, but not zero, during concurrent NADP reduction. These results imply that competition for substrate occurs and suggest that nitrite reduction can successfully compete for reduced ferredoxin, even at high rates...

Nitrite reduction by a copper complex featuring a proton-responsive tripodal ligand is demonstrated. Gaseous nitric oxide was confirmed as the sole NO X by-product in quantitative yield. DFT calculations predict that nitrite reduction occurs via a proton and electron transfer process mediated by the ligand. The reported mechanism parallels nitrite reduction by copper nitrite reductase.

Reduction of nitrite by cell-free preparations of Anabaena cylindrica in the dark has been investigated. Nitrite-reducing activity was recovered in a supernatant fraction. The nitrite reductase system was partially purified by column chromatography on Sephadex G-75. NADPH could serve as an H-donor. NADH was completely inactive. The reduction required ferredoxin which mediated the transfer of el...

Nitrite reduction in either whole, isolated spinach chloroplasts (Spinacia oleracea L.) or in reconstituted spinach chloroplasts is stimulated by a short period of photosynthetic CO(2) fixation in the light prior to nitrite addition. With reconstituted chloroplasts, a similar stimulation can be obtained in nitrite reduction without CO(2) fixation by the addition of dihydroxyacetone phosphate or...

narK mutants of Escherichia coli produce wild-type levels of nitrate reductase but, unlike the wild-type strain, do not accumulate nitrite when grown anaerobically on a glucose-nitrate medium. Comparison of the rates of nitrate and nitrite metabolism in cultures growing anaerobically on glucose-nitrate medium revealed that a narK mutant reduced nitrate at a rate only slightly slower than that i...