Table 1.
Kinetic parameters for MT-ACS1 and AF-ACS2.
| Substrate | Enzyme | Km | kcat | kcat/Km |
| (mM) | (s–1) | (s–1 mM–1) | ||
| Acetate | MT-ACS11 | 3.5 ± 0.1 | 65.4 ± 0.3 | 18.6 ± 0.5 |
| AF-ACS2 | 1.7 ± 0.06 | 35.9 ± 0.58 | 21.2 ± 0.4 | |
| Propionate | MT-ACS11 | 36.5 ± 1.9 | 46.3 ± 0.7 | 1.3 ± 0.04 |
| AF-ACS2 | 3.9 ± 0.02 | 35.7 ± 0.17 | 9.1 ± 0.06 | |
| Butyrate | MT-ACS11 | — | — | — |
| AF-ACS2 | 133.0 ± 14.6 | 1.68 ± 0.07 | 0.013 ± 0.0009 | |
| Valerate | MT-ACS1 | — | — | — |
| AF-ACS2 | Unsaturable | |||
| Isobutyrate | MT-ACS1 | — | — | — |
| AF-ACS2 | Unsaturable | |||
| ATP | MT-ACS11 | 3.3 ± 0.2 | 66.6 ± 0.9 | 20.2 ± 0.9 |
| AF-ACS2 | 2.9 ± 0.01 | 38.1 ± 0.12 | 13.2 ± 0.09 | |
| CoA | MT-ACS1 | 0.19 ± 0.003 | 81.6 ± 0.7 | 423.7 ± 4.7 |
| AF-ACS2 | 0.30 ± 0.003 | 44.3 ± 0.2 | 144.9 ± 1.2 | |
1 Kinetic parameters for MT-ACS1 were determined in the presence of 0.5 mM CoA.