Table I.
Parameter | Wild-type ALAS | R85K | R85L | R85L/T430V |
---|---|---|---|---|
Succinyl-CoA as a substrate | ||||
kcat, min−1 | 10.0 ± 0.2 | 6.4 ± 0.2 | 0.94 ± 0.10 | 0.11 ± 0.03 |
, μM | 2.9 ± 0.1 | 12.4 ± 0.6 | 20.3 ± 1.0 | 9.6 ± 0.8 |
kcat/, min−1 μM−1 | 3.6 ± 0.2 | 0.53 ± 0.04 | 0.050 ± 0.003 | 0.010 ± 0.002 |
, mM | 24.2 ± 0.4 | 20.0 ± 0.4 | 63.1 ± 2.2 | 98.4 ± 3.5 |
kcat/, min−1 mM−1 | 0.43 ± 0.04 | 0.32 ± 0.06 | 0.010 ± 0.002 | 0.001 ± 0.002 |
Octanoyl-CoA as a substrate | ||||
kcat, min−1 | 3.4 ± 0.2 | 10.3 ± 0.4 | 1.8 ± 0.3 | (1.0 ± 0.1) × 10−3 |
, μM | 0.51 ± 0.04 | 1.5 ± 0.04 | 0.55 ± 0.03 | 17.2 ± 0.6 |
kcat/, min−1 μM−1 | 6.8 ± 0.8 | 7.0 ± 0.2 | 3.3 ± 0.1 | (5.6 ± 0.2) × 10−5 |
, mM | 17.1 ± 0.9 | 25.2 ± 1.1 | 55.2 ± 5.0 | 74.2 ± 3.3 |
kcat/, min−1 mM−1 | 0.14 ± 0.01 | 0.52 ± 0.02 | 0.030 ± 0.005 | (1.0 ± 0.08) × 10−5 |
Butyryl-CoA as a Substrate | ||||
kcat, min−1 | 6.3 ± 0.3 | 10.2 ± 0.3 | 2.01 ± 0.08 | 0.060 ± 0.002 |
, μM | 6.1 ± 0.09 | 2.7 ± 0.1 | 9.3 ± 1.0 | 0.54 ± 0.03 |
kcat/, min−1 μM−1 | 1.0 ± 0.1 | 3.7 ± 0.4 | 0.21 ± 0.04 | 0.03 ± 0.002 |
, mM | 29.3 ± 4.6 | 17.2 ± 0.7 | 70.3 ± 6.6 | 88.2 ± 3.9 |
kcat/, min−1 mM−1 | 0.26 ± 0.03 | 0.50 ± 0.01 | 0.030 ± 0.005 | (6.1 ± 0.8) × 10−4 |
β-Hydroxybutyryl-CoA as a Substrate | ||||
kcat, min−1 | 4.0 ± 0.8 | 2.8 ± 0.1 | 0.65 ± 0.03 | (1.0 ± 0.2) × 10−4 |
, μM | 9.8 ± 1.0 | 5.5 ± 0.2 | 6.1 ± 0.8 | 74.2 ± 0.6 |
kcat/, min−1 μM−1 | 0.41 ± 0.04 | 0.51 ± 0.04 | 0.11 ± 0.02 | (1.3 ± 0.4) × 10−6 |
, mM | 22.1 ± 0.8 | 18.2 ± 3.2 | 59.1 ± 4.7 | 92.2 ± 6.0 |
kcat/, min−1 mM−1 | 0.17 ± 0.06 | 0.14 ± 0.03 | 0.011 ± 0.003 | (1.0 ± 0.3) × 10−6 |
Glutaryl-CoA as a Substrate | ||||
kcat, min−1 | 7.0 ± 0.4 | 0.30 ± 0.03 | 2.2 ± 0.1 | n/d |
, μM | 17.0 ± 1.6 | 7.5 ± 0.6 | 30.1 ± 1.1 | n/d |
kcat/, min−1 μM−1 | 0.41 ± 0.05 | 0.04 ± 0.003 | 0.07 ± 0.006 | n/d |
, mM | 28.4 ± 0.8 | 21.2 ± 0.2 | 70.6 ± 4.2 | n/d |
kcat/, min−1 mM−1 | 0.29 ± 0.02 | 0.010 ± 0.002 | (8.0 ± 0.7) × 10−4 | n/d |
n/d, not determined.