Nitrite oxidoreductase

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. NXR is responsible for producing almost all nitrate found in nature.[1]

NXR belongs to the class of EC numbers 1.7.2- [2][3] where 1 describes an oxidoreductase, 1.7 describes nitrogen compounds as donors, and 1.7.2- describes cytochromes as acceptors.[3]

  1. ^ Chicano, Tadeo Moreno; Dietrich, Lea; de Almeida, Naomi M.; Akram, Mohd.; Hartmann, Elisabeth; Leidreiter, Franziska; Leopoldus, Daniel; Mueller, Melanie; Sánchez, Ricardo; Nuijten, Guylaine H. L.; Reimann, Joachim; Seifert, Kerstin-Anikó; Schlichting, Ilme; van Niftrik, Laura; Jetten, Mike S. M. (2021-07-15). "Structural and functional characterization of the intracellular filament-forming nitrite oxidoreductase multiprotein complex". Nature Microbiology. 6 (9): 1129–1139. doi:10.1038/s41564-021-00934-8. ISSN 2058-5276. PMC 8387239. PMID 34267357.
  2. ^ Caspi, Ron; Billington, Richard; Fulcher, Carol A; Keseler, Ingrid M; Kothari, Anamika; Krummenacker, Markus; Latendresse, Mario; Midford, Peter E; Ong, Quang; Ong, Wai Kit; Paley, Suzanne; Subhraveti, Pallavi; Karp, Peter D (2017-10-20). "The MetaCyc database of metabolic pathways and enzymes". Nucleic Acids Research. 46 (D1): D633–D639. doi:10.1093/nar/gkx935. ISSN 0305-1048. PMC 5753197. PMID 29059334.
  3. ^ a b "ENZYME: 1.7.2.-". enzyme.expasy.org. Retrieved 2023-10-19.