KEGG   PATHWAY: hsa00910Help
hsa00910                    Pathway                                

Nitrogen metabolism - Homo sapiens (human)
The biological process of the nitrogen cycle is a complex interplay among many microorganisms catalyzing different reactions, where nitrogen is found in various oxidation states ranging from +5 in nitrate to -3 in ammonia. The core nitrogen cycle involves four reduction pathways and two oxidation pathways. Nitrogen fixation [MD:M00175] is the process of reducing atmospheric molecular nitrogen to ammonia, a biologically useful reduced form incorporated into amino acids and other vital compounds. The ability of fixing atmospheric nitrogen by the nitrogenase enzyme complex is present in restricted prokaryotes (diazotrophs). The other reduction pathways are assimilatory nitrate reduction [MD:M00531] and dissimilatory nitrate reduction [MD:M00530] both for conversion to ammonia, and denitrification [MD:M00529]. Denitrification is a respiration in which nitrate or nitrite is reduced as a terminal electron acceptor under low oxygen or anoxic conditions, producing gaseous nitrogen compounds (N2, NO and N2O) to the atmosphere. The two oxidation pathways are nitrification [MD:M00528] and anaerobic ammonium oxidation (anammox). Nitrification is the oxidation of ammonia (NH3) with oxygen into nitrite followed by the oxidation of nitrite into nitrate. The first step is performed by ammonia-oxidizing microorganisms (e.g., Nitrosomonas and Nitrosococcus) and the second step by nitrite-oxidizing microorganisms (e.g., Nitrobacter). Anammox is a biochemical process of oxidizing ammonium (NH4+) into dinitrogen gas (N2) using nitrite as an electron acceptor. It occurs in the anammoxosome, a membrane bound compartment inside the cytoplasm, of anammox bacteria (e.g., Planctomycetes).
Metabolism; Energy metabolism
BRITE hierarchy
Pathway map
hsa00910  Nitrogen metabolism

Ortholog table
H00164  Carbamoyl phosphate synthetase I deficiency
H00923  Congenital systemic glutamine deficiency (CSGD)
D07130  Carglumic acid (JAN/USAN/INN)
Other DBs
BSID: 83025
GO: 0006807
Homo sapiens (human) [GN:hsa]
2747  GLUD2; glutamate dehydrogenase 2 [KO:K00261] [EC:]
2746  GLUD1; glutamate dehydrogenase 1 [KO:K00261] [EC:]
2752  GLUL; glutamate-ammonia ligase [KO:K01915] [EC:]
1373  CPS1; carbamoyl-phosphate synthase 1 [KO:K01948] [EC:]
377677  CA13; carbonic anhydrase 13 [KO:K01672] [EC:]
759  CA1; carbonic anhydrase 1 [KO:K01672] [EC:]
765  CA6; carbonic anhydrase 6 [KO:K01672] [EC:]
766  CA7; carbonic anhydrase 7 [KO:K01672] [EC:]
771  CA12; carbonic anhydrase 12 [KO:K01672] [EC:]
11238  CA5B; carbonic anhydrase 5B [KO:K01672] [EC:]
23632  CA14; carbonic anhydrase 14 [KO:K01672] [EC:]
768  CA9; carbonic anhydrase 9 [KO:K01672] [EC:]
761  CA3; carbonic anhydrase 3 [KO:K01672] [EC:]
763  CA5A; carbonic anhydrase 5A [KO:K01672] [EC:]
767  CA8; carbonic anhydrase 8 [KO:K01672] [EC:]
760  CA2; carbonic anhydrase 2 [KO:K18245] [EC:]
762  CA4; carbonic anhydrase 4 [KO:K18246] [EC:]
C00011  CO2
C00014  Ammonia
C00025  L-Glutamate
C00058  Formate
C00064  L-Glutamine
C00088  Nitrite
C00169  Carbamoyl phosphate
C00192  Hydroxylamine
C00244  Nitrate
C00288  HCO3-
C00488  Formamide
C00533  Nitric oxide
C00697  Nitrogen
C00726  Nitrile
C00887  Nitrous oxide
C01417  Cyanate
C01563  Carbamate
C05361  Hydrazine
C06058  Nitroalkane
Scott JD, Ludwig RA
Azorhizobium caulinodans electron-transferring flavoprotein N electrochemically couples pyruvate dehydrogenase complex activity to N2 fixation.
Microbiology 150:117-26 (2004)
Kneip C, Lockhart P, Voss C, Maier UG
Nitrogen fixation in eukaryotes--new models for symbiosis.
BMC Evol Biol 7:55 (2007)
Whittaker M, Bergmann D, Arciero D, Hooper AB
Electron transfer during the oxidation of ammonia by the chemolithotrophic bacterium Nitrosomonas europaea.
Biochim Biophys Acta 1459:346-55 (2000)
Cabello P, Roldan MD, Moreno-Vivian C
Nitrate reduction and the nitrogen cycle in archaea.
Microbiology 150:3527-46 (2004)
Stolz JF, Basu P
Evolution of nitrate reductase: molecular and structural variations on a common function.
Morozkina EV, Zvyagilskaya RA
Nitrate reductases: structure, functions, and effect of stress factors.
Biochemistry (Mosc) 72:1151-60 (2007)
Jetten MS, Niftrik L, Strous M, Kartal B, Keltjens JT, Op den Camp HJ
Biochemistry and molecular biology of anammox bacteria.
Crit Rev Biochem Mol Biol 44:65-84 (2009)
Luesken FA, Wu ML, Op den Camp HJ, Keltjens JT, Stunnenberg H, Francoijs KJ, Strous M, Jetten MS
Effect of oxygen on the anaerobic methanotroph 'Candidatus Methylomirabilis oxyfera': kinetic and transcriptional analysis.
Environ Microbiol 14:1024-34 (2012)
Daims H, Lebedeva EV, Pjevac P, Han P, Herbold C, Albertsen M, Jehmlich N, Palatinszky M, Vierheilig J, Bulaev A, Kirkegaard RH, von Bergen M, Rattei T, Bendinger B, Nielsen PH, Wagner M
Complete nitrification by Nitrospira bacteria.
Nature 528:504-9 (2015)
van Kessel MA, Speth DR, Albertsen M, Nielsen PH, Op den Camp HJ, Kartal B, Jetten MS, Lucker S
Complete nitrification by a single microorganism.
Nature 528:555-9 (2015)
KO pathway

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