Table 1 Changes of free energy (ΔG0′; pH = 7, T = 298 K) for each AOB metabolic reaction
From: Back flux during anaerobic oxidation of butane supports archaea-mediated alkanogenesis
Index | Reactiona | ΔG0′ (kJ mol−1) | Stoi.c | Enzymed | Ex = −0.414Ve | Ex = −0.22Vf |
---|---|---|---|---|---|---|
1 | C4H10 (g) + CoM-S-S-CoB == C4H9-S-CoM + HS-CoB | 16.900 | 1 | ACR | 16.900 | 16.900 |
2 | HS-CoM + HS-CoB + 2Fdred + 2H+ + 2F420 == CoM-S-S-CoB + 2Fdox + 2F420H2 | 7.141 | 1 | Hdr-FrhB | 7.141 | 7.141 |
3 | C4H9-S-CoM + CoA + H2O + 2X == Butyryl-CoA + HS-CoM + 2XH2 | Related to Exb | 1 | ? | 104.003 | 29.119 |
4 | Butyryl-CoA + 2NAD+ + 2Fdred == Crotonyl-CoA + 2NADH + 2Fdox | 25.090 | 1 | Bcd-Etf | 25.090 | 25.090 |
5 | Crotonyl-CoA + H2O == (S)-3-Hydroxybutyryl-CoA | 0.300 | 1 | Ech | 0.300 | 0.300 |
6 | (S)-3-Hydroxybutyryl-CoA + NAD+ == Acetoacetyl-CoA + NADH + H+ | 12.545 | 1 | HADH | 12.545 | 12.545 |
7 | Acetoacetyl-CoA + CoA == 2 Acetyl-CoA | −28.100 | 1 | ACAT | −28.100 | −28.100 |
8 | NADH + H+ + MQ == NAD+ + MQH2 | −46.320 | 5 | NDH | −46.320 | −46.320 |
9 | Acetyl-CoA + H4MPT + 2 Fdox + H2O == CH3-H4MPT + CoA + CO2 (g) + 2 Fdred + 2H+ | 66.114 | 2 | ACS-CODH | 66.114 | 66.114 |
10 | CH3-H4MPT + NAD+ == CH2 = H4MPT + NADH + H+ | 1.140 | 2 | Met | 1.140 | 1.140 |
11 | CH2 = H4MPT + F420 + H+ == CH ≡ H4MPT+ + F420H2 | −6.500g | 2 | Mtd | −6.500 | −6.500 |
12 | CH ≡ H4MPT+ + H2O == HCO-H4MPT + H+ | 2.000g | 2 | Mch | 2.000 | 2.000 |
13 | HCO-H4MPT + MF == HCO-MF + H4MPT | −21.100g | 2 | Ftr | −21.100 | −21.100 |
14 | HCO-MF + H2O + 2Fdox == CO2 (g) + MF + 2H+ + 2Fdred | 0.598 | 2 | Fwd | 0.598 | 0.598 |
15 | F420H2 + MQ == F420 + MQH2 | −50.180 | 4 | Fqo | −50.180 | −50.180 |
16 | 2 Fdred + 2H+ + MQ == 2 Fdox + MQH2 | −81.060 | 2 | Nuo | −81.060 | −81.060 |
17 | MQH2 + X == MQ + XH2 | Related to Exb | 11 | ? MHCs | 64.462 | 27.020 |