| 2 (2E,6E)-farnesyl diphosphate→presqualene diphosphate + diphosphate (EC 2.5.1.103; 2.5.1.21; 2.5.1.96) |
| mRNA_8223 (16591) |
Squalene synthase:
presqualene diphosphate + NAD(P)H + H+→squalene + NAD(P)+ + diphosphate (EC 2.5.1.21) |
| mRNA_8223 (16591) |
| squalene + dioxygen + a reduced [NADPH-hemoprotein reductase]→(3S)-2,3-epoxy-2,3-dihydrosqualene + an oxidized [NADPH-hemoprotein reductase] + H2O (EC 1.14.14.17) |
| No genes |
Lanosterol synthase:
(3S)-2,3-epoxy-2,3-dihydrosqualene→lanosterol (EC 5.4.99.7) |
| mRNA_872 (9240) |
| lanosterol + 3 dioxygen + 3 a reduced [NADPH-hemoprotein reductase]→4,4-dimethyl-5-α-cholesta-8,14,24-trien-3-β-ol + formate + 3 an oxidized [NADPH-hemoprotein reductase] + H+ + 4 H2O (EC 1.14.14.154) |
| No genes |
Delta(14)-sterol reductase (in reverse):
4,4-dimethyl-5-α-cholesta-8,14,24-trien-3-β-ol + NADPH + H+→14-demethyllanosterol + NADP+ (EC 1.3.1.70) |
| No genes |
| 14-demethyllanosterol + 6 a ferrocytochrome b5 + 3 dioxygen + 5 H+→4α-carboxy-4β-methyl-5α-cholesta-8,24-dien-3β-ol + 6 a ferricytochrome b5 + 4 H2O (EC 1.14.18.9) |
| mRNA_8272 (16640) |
Sterol-4-alpha-carboxylate 3-dehydrogenase (decarboxylating):
4α-carboxy-4β-methyl-5α-cholesta-8,24-dien-3β-ol + NAD(P)+→3-dehydro-4-methylzymosterol + CO2 + NAD(P)H (EC 1.1.1.170) |
| No genes |
3-keto-steroid reductase (in reverse):
3-dehydro-4-methylzymosterol + NADPH + H+→4α-methyl-zymosterol + NADP+ (EC 1.1.1.270) |
| No genes |
| 4α-methyl-zymosterol + 6 a ferrocytochrome b5 + 3 dioxygen + 5 H+→4α-carboxy-5α-cholesta-8,24-dien-3β-ol + 6 a ferricytochrome b5 + 4 H2O (EC 1.14.18.9) |
| mRNA_8272 (16640) |
Sterol-4-alpha-carboxylate 3-dehydrogenase (decarboxylating):
4α-carboxy-5α-cholesta-8,24-dien-3β-ol + NAD(P)+→zymosterone + CO2 + NAD(P)H (EC 1.1.1.170) |
| No genes |
3-keto-steroid reductase (in reverse):
zymosterone + NADPH + H+→zymosterol + NADP+ (EC 1.1.1.270) |
| No genes |
Cholestenol Delta-isomerase (in reverse):
zymosterol→5α-cholesta-7,24-dien-3β-ol (EC 5.3.3.5) |
| No genes |
| 5α-cholesta-7,24-dien-3β-ol + 2 a ferrocytochrome b5 + dioxygen + 2 H+→7-dehydrodesmosterol + 2 a ferricytochrome b5 + 2 H2O (EC 1.14.19.20) |
| No genes |
7-dehydrocholesterol reductase (in reverse):
7-dehydrodesmosterol + NADPH + H+→desmosterol + NADP+ (EC 1.3.1.21) |
| No genes |
Delta(24)-sterol reductase (in reverse):
desmosterol + NADPH + H+→cholesterol + NADP+ (EC 1.3.1.72) |
| No genes |
Links:
Candidate genes for each reaction are identified from best hits to MetaCyc; by matching EC numbers (which are assigned by TIGRFam, SEED, or best hits to KEGG); or by matching SEED roles to KEGG reactions to MetaCyc reactions. See the "Protein" tab of each gene for more information