Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.7.1.4 (nitrite reductase)
 1,847 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study provides preliminary evidence that NO production could be a general attribute of algae. Anabaena doliolum was found to be a better NO producer than Scenedesmus and Synechoccocus. Experiments conducted with inhibitors of photosynthesis (DCMU), ATP synthesis (DCCD), and the uncoupler (2,4-DNP) and its analog arsenate clearly revealed that inhibition of nitrite assimilation through the blockage of nitrite reductase (NiR) is primarily responsible for NO emission. A linear relationship between nitrite concentration in the culture medium and NO in the exhaust gas supports the view that accumulation of nitrite is responsible for NO formation. A failure of Scenedesmus, grown in the medium substituted with W for Mo, to produce either NO/NO-2 in light or a 'light-off' peak, and a resumption of these activities upon the addition of Mo proved beyond doubt that a functional nitrate reductase (NR) is necessary for the production of nitrite and NO by algae grown on nitrate as the nitrogen source. Moreover, the appearance of a NO peak immediately after nitrite supplementation under dark conditions in W-substituted cultures with or without glucose ruled out an enzymatic role of NR in NO emission.
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PMID:Studies on nitric oxide (NO) formation by the green alga Scenedesmus obliquus and the diazotrophic cyanobacterium Anabaena doliolum. 1052 Apr 83

Methyl viologen and phenazine methosulfate (photosystem I electron acceptors), 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (DCMU, electron-transport inhibitor), and methylamine (photophosphorylation uncoupler) were used to study the dependence of nitrite reduction on electron transport in chloroplasts.DCMU, methyl viologen, and phenazine methosulfate markedly inhibited, whereas methylamine stimulated NO(2) (-) reduction in isolated, intact spinach (Spinacia oleracea L.) chloroplasts. The addition of DCMU to leaf sections of spinach and corn, (Zea mays L. var. XL81), incubated with No(3) (-), caused no inhibition of nitrate reduction but inhibited nitrite reduction leading to the accumulation of NO(2) (-) in the light. The addition of methylamine to comparable leaf sections did not affect either nitrate or nitrite reduction.WE CONCLUDED THAT: (a) nitrite reduction is functionally associated with the electron transport arising from the light reactions of the chloroplast and this provides additional support for the localization of nitrite reductase in the chloroplast; (b) nitrite reduction is associated with photosystem I and ferredoxin is the most likely donor in leaf tissue; and (c) ATP is not involved directly in nitrite reduction. However, ATP synthesis, by regulating electron flow to photosystem I, can affect nitrite reduction in the light.
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PMID:Dependence of nitrite reduction on electron transport chloroplasts. 1665 12