Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Fe2+ | initial and final states contain Fe(II) heme, catalytic heme in the Fe2+ state | Azotobacter vinelandii |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
hydroxylamine + ferrocytochrome c | Azotobacter vinelandii | cf. EC 1.7.99.1 | NH3 + H2O + ferricytochrome c | - |
? | |
nitrite + 4 ferrocytochrome c + 5 H+ | Azotobacter vinelandii | cf. EC 1.7.2.6 | hydroxylamine + H2O + 4 ferricytochrome c | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Azotobacter vinelandii | - |
several strains | - |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
NH3 + 2 H2O + 6 ferricytochrome c = nitrite + 6 ferrocytochrome c + 7 H+ | reaction mechanism, overview. NO2- binds to the enzyme ccNIR catalytic heme in the Fe2+ state, accepts two protons, and releases H2O to form a moiety formally written as Fe(II)-[NO+]. The key mechanistic challenge in reducing NO2- is to avoid or overcome formation of the terminal Fe(II)-NO thermodynamic sink through one-electron reduction of Fe(II)-[NO+]. Enzyme ccNIR achieves this by two proton-coupled electron transfer reductions that promptly reduce Fe(II)-[NO+] to Fe(II)-[HNO]. The process involves recharging of the catalytic heme with electrons obtained through transfer from the other hemes of the enzyme and of the heme environment with protons | Azotobacter vinelandii |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
hydroxylamine + ferrocytochrome c | cf. EC 1.7.99.1 | Azotobacter vinelandii | NH3 + H2O + ferricytochrome c | - |
? | |
nitrite + 4 ferrocytochrome c + 5 H+ | cf. EC 1.7.2.6 | Azotobacter vinelandii | hydroxylamine + H2O + 4 ferricytochrome c | - |
? |
Synonyms | Comment | Organism |
---|---|---|
ccNiR | - |
Azotobacter vinelandii |
multiheme cytochrome c nitrite reductase | - |
Azotobacter vinelandii |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
cytochrome c | heme | Azotobacter vinelandii | |
heme | catalytic heme in the Fe2+ state | Azotobacter vinelandii |
General Information | Comment | Organism |
---|---|---|
additional information | comparison of reaction mechanisms of nitrogenase, EC 1.18.6.1, and multiheme cytochrome c nitrite reductase, ccNIR, EC 1.7.2.2, overview | Azotobacter vinelandii |