Cytochrome c nitrite reductase (ccNIR) is a multiheme enzyme that converts nitrite to ammonia on each active site. (wikipedia.org)
The synthesis of the modified tetrapyrrole known as d(1) haem requires several dedicated proteins which are coded for by a set of genes that are often found adjacent to the structural gene, nirS, for cytochrome cd(1) nitrite reductase. (ox.ac.uk)
A NirN-d(1) haem complex was demonstrated to release the cofactor to a semi-apo form of cytochrome cd(1) from which d(1) was extracted, suggesting a role for NirN in the assembly of cytochrome cd(1) (NirS). (ox.ac.uk)
Although the d1 heme is only found in the cytochrome cd1, the importance of this enzyme is becoming ever more evident as it vital for the environmentally important ANAMMOX process whereby ammonia is oxidised by nitrite under anaerobic conditions and has recently been implicated in playing a key role in the anaerobic oxidation of methane. (ukri.org)
Heme2
However, we have recently demonstrated that heme and a structurally related macrocycle, heme d1, can be made by a completely novel pathway that involves the cannibalism of another modified tetrapyrrole, a compound called siroheme, the prosthetic group of sulphite and nitrite reductase. (ukri.org)
It is believed that d1 heme has been adopted for respiratory nitrite reduction because it is tuned to permit nitrite reduction only as far as nitric oxide and not to allow the onward reduction to ammonia that is catalysed by siroheme. (ukri.org)
Nitrate Reductase5
Assimilatory nitrate reductase is an enzyme of the assimilative metabolism involved in reduction of nitrate to nitrite. (wikipedia.org)
The different antioxidant enzymes show disparate behaviour with signalling molecule NO. The activity of catalase, guaiacol peroxidase and nitrate reductase were upregulated whereas ascorbate peroxidase was downregulated with NO. The elevated activities of antioxidant and NO accumulation might be responsible for detoxifying the detrimental effect of salinity in B. juncea . (vegetosindia.org)
Datta R, Sharma R (1999) Temporal and spatial regulation of nitrate reductase and nitrite reductase in greening maize leaves. (vegetosindia.org)
Nitrite reductase refers to any of several classes of enzymes that catalyze the reduction of nitrite. (wikipedia.org)
This review aims to describe the structural characteristics of superoxide reductases (SORs) and mechanistic aspects of biological superoxide anion reduction. (unl.pt)
The oxidation level allows nitrite to bond more strongly than to the +3 state due to increased pi backbonding. (wikipedia.org)
An incoming electron reduces the Cu from oxidation state (II) to (I). This change facilitates a shift in nitrite binding so that the nitrogen is bound to Cu, and one oxygen has an extended bond length due to hydrogen bonding. (wikipedia.org)
This electronic effect transfers electron density into the nitrite antibonding orbital between nitrogen and oxygen. (wikipedia.org)
Gene1
d(1) haem biogenesis - assessing the roles of three nir gene products. (ox.ac.uk)
Activity1
Ascenzi P, Tundo GR, Coletta M. (2018) The nitrite reductase activity of ferrous human hemoglobin:haptoglobin 1-1 and 2-2 complexes . (uniroma2.it)
Product1
The reduced d hemes bind nitrite and convert it to product. (wikipedia.org)
Formation1
of the machineries that are necessary for formation of the thioether bonds between protein and haem, are fully understood. (silverchair.com)
Type1
This Histidine is bound to the Type 2 Cu center responsible for binding and reducing nitrite. (wikipedia.org)
Nitrate6
Assimilatory nitrate reductase is an enzyme of the assimilative metabolism involved in reduction of nitrate to nitrite. (wikipedia.org)
This Week's Citation Classic CC/NUMBER 29 JULY 20,1981 Hewitt E J. Assimilatory nitrate-nitrite reduction. (studyres.com)
The most exciting early result was the first experimental reproduction of 'whiptail' in cauliflowers grown in molybdenum deficient sand cultures using a new method for nutrient purification.2 Continued work on 'whiptail,' studying effects of nitrogen sources with S.C. Agarwala and induction of nitrate reductase with M.M.R.K. Afridi, established my joint interests in inorganic nitrogen metabolism and micronutrients. (studyres.com)
Isolation of the tungsten analogue of nitrate reductase with B.A. Notton provided the rationale for current uses of tungsten and helped towards further understanding of 'whiptail. (studyres.com)
In normal haemoglobin (Hb), 4 globin chains surround an iron-containing porphyrin pigment molecule known as haem. (umqaa.com)
Electron2
This electronic effect transfers electron density into the nitrite antibonding orbital between nitrogen and oxygen. (wikipedia.org)
An incoming electron reduces the Cu from oxidation state (II) to (I). This change facilitates a shift in nitrite binding so that the nitrogen is bound to Cu, and one oxygen has an extended bond length due to hydrogen bonding. (wikipedia.org)
Oxygen2
Spectrophotometric confirmation for oxygen ligation to the reduced haem d(1) of Pseudomonas nautica nitrite reductase. (unl.pt)
Each haem molecule contains a ferrous ion (Fe2+), to which oxygen reversibly binds. (umqaa.com)
Center1
This Histidine is bound to the Type 2 Cu center responsible for binding and reducing nitrite. (wikipedia.org)