K01455  E3.5.1.49; formamidase [EC:3.5.1.49]
       K02575  NRT2, narK, nrtP, nasA; MFS transporter, NNP family, nitrate/nitrite transporter
       K15576  nrtA, nasF, cynA; nitrate/nitrite transport system substrate-binding protein
       K15577  nrtB, nasE, cynB; nitrate/nitrite transport system permease protein
       K15578  nrtC, nasD; nitrate/nitrite transport system ATP-binding protein [EC:7.3.2.4]
       K15579  nrtD, cynD; nitrate/nitrite transport system ATP-binding protein
       K00367  narB; ferredoxin-nitrate reductase [EC:1.7.7.2]
       K10534  NR; nitrate reductase (NAD(P)H) [EC:1.7.1.1 1.7.1.2 1.7.1.3]
       K00370  narG, narZ, nxrA; nitrate reductase / nitrite oxidoreductase, alpha subunit [EC:1.7.5.1 1.7.99.-]
       K00371  narH, narY, nxrB; nitrate reductase / nitrite oxidoreductase, beta subunit [EC:1.7.5.1 1.7.99.-]
       K00374  narI, narV; nitrate reductase gamma subunit [EC:1.7.5.1 1.7.99.-]
       K02567  napA; nitrate reductase (cytochrome) [EC:1.9.6.1]
       K02568  napB; nitrate reductase (cytochrome), electron transfer subunit
       K00372  nasC,  nasA; assimilatory nitrate reductase catalytic subunit [EC:1.7.99.-]
       K00360  nasB; assimilatory nitrate reductase electron transfer subunit [EC:1.7.99.-]
       K17877  NIT-6; nitrite reductase (NAD(P)H) [EC:1.7.1.4]
       K26139  nasD, nasB; nitrite reductase [NAD(P)H] large subunit [EC:1.7.1.4]
       K26138  nasE; nitrite reductase [NAD(P)H] small subunit [EC:1.7.1.4]
       K00361  nasB; nitrite reductase [NAD(P)H] [EC:1.7.1.4]
       K00362  nirB; nitrite reductase (NADH) large subunit [EC:1.7.1.15]
       K00363  nirD; nitrite reductase (NADH) small subunit [EC:1.7.1.15]
       K00366  nirA; ferredoxin-nitrite reductase [EC:1.7.7.1]
       K03385  nrfA; nitrite reductase (cytochrome c-552) [EC:1.7.2.2]
       K15876  nrfH; cytochrome c nitrite reductase small subunit
       K00368  nirK; nitrite reductase (NO-forming) [EC:1.7.2.1]
       K15864  nirS; nitrite reductase (NO-forming) / hydroxylamine reductase [EC:1.7.2.1 1.7.99.1]
       K04561  norB; nitric oxide reductase subunit B [EC:1.7.2.5]
       K02305  norC; nitric oxide reductase subunit C
       K15877  CYP55; fungal nitric oxide reductase [EC:1.7.1.14]
       K00376  nosZ; nitrous-oxide reductase [EC:1.7.2.4]
       K27148  nod; nitric oxide dismutase
       K02586  nifD; nitrogenase molybdenum-iron protein alpha chain [EC:1.18.6.1]
       K02591  nifK; nitrogenase molybdenum-iron protein beta chain [EC:1.18.6.1]
       K02588  nifH; nitrogenase iron protein NifH
       K00531  anfG; nitrogenase delta subunit [EC:1.18.6.1]
       K22896  vnfD; vanadium-dependent nitrogenase alpha chain [EC:1.18.6.2]
       K22897  vnfK; vanadium-dependent nitrogenase beta chain [EC:1.18.6.2]
       K22898  vnfG; vanadium nitrogenase delta subunit [EC:1.18.6.2]
       K22899  vnfH; vanadium nitrogenase iron protein
       K20932  K20932; hydrazine synthase subunit [EC:1.7.2.7]
       K20933  K20933; hydrazine synthase subunit [EC:1.7.2.7]
       K20934  K20934; hydrazine synthase subunit [EC:1.7.2.7]
       K20935  hdh; hydrazine dehydrogenase [EC:1.7.2.8]
       K10944  pmoA-amoA; methane/ammonia monooxygenase subunit A [EC:1.14.18.3 1.14.99.39]
       K10945  pmoB-amoB; methane/ammonia monooxygenase subunit B
       K10946  pmoC-amoC; methane/ammonia monooxygenase subunit C
       K05601  hcp; hydroxylamine reductase [EC:1.7.99.1]
       K10535  hao; hydroxylamine dehydrogenase [EC:1.7.2.6]
       K00459  ncd2, npd; nitronate monooxygenase [EC:1.13.12.16]
       K19823  NAO; nitroalkane oxidase [EC:1.7.3.1]
       K01501  E3.5.5.1; nitrilase [EC:3.5.5.1]
       K15371  GDH2; glutamate dehydrogenase [EC:1.4.1.2]
       K00260  gudB, rocG; glutamate dehydrogenase [EC:1.4.1.2]
       K00261  GLUD1_2, gdhA; glutamate dehydrogenase (NAD(P)+) [EC:1.4.1.3]
       K00262  E1.4.1.4, gdhA; glutamate dehydrogenase (NADP+) [EC:1.4.1.4]
       K01915  glnA, GLUL; glutamine synthetase [EC:6.3.1.2]
       K00264  GLT1; glutamate synthase (NADH) [EC:1.4.1.14]
       K00265  gltB; glutamate synthase (NADPH) large chain [EC:1.4.1.13]
       K00266  gltD; glutamate synthase (NADPH) small chain [EC:1.4.1.13]
       K00284  GLU, gltS; glutamate synthase (ferredoxin) [EC:1.4.7.1]
       K01948  CPS1; carbamoyl-phosphate synthase (ammonia) [EC:6.3.4.16]
       K01725  cynS; cyanate lyase [EC:4.2.1.104]
       K00926  arcC; carbamate kinase [EC:2.7.2.2]
       K01672  CA; carbonic anhydrase [EC:4.2.1.1]
       K18245  CA2; carbonic anhydrase 2 [EC:4.2.1.1]
       K18246  CA4; carbonic anhydrase 4 [EC:4.2.1.1]
       K01673  cynT, can; carbonic anhydrase [EC:4.2.1.1]
       K01674  cah; carbonic anhydrase [EC:4.2.1.1]
       K01743  E4.2.1.1; carbonic anhydrase [EC:4.2.1.1]