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Nitrite oxidoreductase (NOR or NXR) is an enzyme involved in nitrification.It is the last step in the process of aerobic ammonia oxidation, which is carried out by two groups of nitrifying bacteria: ammonia oxidizers such as Nitrosospira, Nitrosomonas, and Nitrosococcus convert ammonia to nitrite, while nitrite oxidizers such as Nitrobacter and Nitrospira oxidize nitrite to nitrate.
This problem is solved by using a nitrite oxidoreductase to produce enough proton-motive force to run part of the electron transport chain in reverse, causing complex I to generate NADH. [63] [64] Prokaryotes control their use of these electron donors and acceptors by varying which enzymes are produced, in response to environmental conditions. [65]
Nitrate reductase (NADH) (EC 1.7.1.1, assimilatory nitrate reductase, NADH-nitrate reductase, NADH-dependent nitrate reductase, assimilatory NADH: nitrate reductase, nitrate reductase (NADH 2), NADH 2: nitrate oxidoreductase) is an enzyme with systematic name nitrite: NAD + oxidoreductase.
The systematic name of this enzyme class is ammonium-hydroxide:NAD(P)+ oxidoreductase. Other names in common use include nitrite reductase (reduced nicotinamide adenine dinucleotide , (phosphate)) , NADH-nitrite oxidoreductase , NADPH-nitrite reductase , assimilatory nitrite reductase , nitrite reductase [NAD(P)H2] , and NAD(P)H2:nitrite ...
The conversion of nitrite to nitrate is facilitated by nitrite-oxidizing bacteria. The genus Nitrobacter is widely distributed in both aquatic and terrestrial environments. [ 2 ] Nitrifying bacteria have an optimum growth between 77 and 86 °F (25 and 30 °C), and cannot survive past the upper limit of 120 °F (49 °C) or the lower limit of 32 ...
Nitrite oxidation is much simpler, with nitrite being oxidized by the enzyme nitrite oxidoreductase coupled to proton translocation by a very short electron transport chain, again leading to very low growth rates for these organisms. Oxygen is required in both ammonia and nitrite oxidation, meaning that both nitrosifying and nitrite-oxidizing ...
NADH dehydrogenase → plastoquinol → b 6 f → cyt c 6 → cyt aa 3 → O 2. where the mobile electron carriers are plastoquinol and cytochrome c 6, while the proton pumps are NADH dehydrogenase, cyt b 6 f and cytochrome aa 3 (member of the COX3 family). Cyanobacteria are the only bacteria that produce oxygen during photosynthesis.
C 2 photosynthesis (also called glycine shuttle and photorespiratory CO 2 pump) is a CCM that works by making use of – as opposed to avoiding – photorespiration. It performs carbon refixation by delaying the breakdown of photorespired glycine, so that the molecule is shuttled from the mesophyll into the bundle sheath .