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. 2009 Jun 26;18(9):1847–1859. doi: 10.1002/pro.195

Table I.

Comparison of Steady-State Kinetic Constants for Wild-type ALAS, R85K, R85L, and R85L/T430V with CoA Derivatives as Substrates

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
Inline graphic, μM 2.9 ± 0.1 12.4 ± 0.6 20.3 ± 1.0 9.6 ± 0.8
kcat/Inline graphic, min−1 μM−1 3.6 ± 0.2 0.53 ± 0.04 0.050 ± 0.003 0.010 ± 0.002
Inline graphic, mM 24.2 ± 0.4 20.0 ± 0.4 63.1 ± 2.2 98.4 ± 3.5
kcat/Inline graphic, 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
Inline graphic, μM 0.51 ± 0.04 1.5 ± 0.04 0.55 ± 0.03 17.2 ± 0.6
kcat/Inline graphic, min−1 μM−1 6.8 ± 0.8 7.0 ± 0.2 3.3 ± 0.1 (5.6 ± 0.2) × 10−5
Inline graphic, mM 17.1 ± 0.9 25.2 ± 1.1 55.2 ± 5.0 74.2 ± 3.3
kcat/Inline graphic, 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
Inline graphic, μM 6.1 ± 0.09 2.7 ± 0.1 9.3 ± 1.0 0.54 ± 0.03
kcat/Inline graphic, min−1 μM−1 1.0 ± 0.1 3.7 ± 0.4 0.21 ± 0.04 0.03 ± 0.002
Inline graphic, mM 29.3 ± 4.6 17.2 ± 0.7 70.3 ± 6.6 88.2 ± 3.9
kcat/Inline graphic, 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
Inline graphic, μM 9.8 ± 1.0 5.5 ± 0.2 6.1 ± 0.8 74.2 ± 0.6
kcat/Inline graphic, min−1 μM−1 0.41 ± 0.04 0.51 ± 0.04 0.11 ± 0.02 (1.3 ± 0.4) × 10−6
Inline graphic, mM 22.1 ± 0.8 18.2 ± 3.2 59.1 ± 4.7 92.2 ± 6.0
kcat/Inline graphic, 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
Inline graphic, μM 17.0 ± 1.6 7.5 ± 0.6 30.1 ± 1.1 n/d
kcat/Inline graphic, min−1 μM−1 0.41 ± 0.05 0.04 ± 0.003 0.07 ± 0.006 n/d
Inline graphic, mM 28.4 ± 0.8 21.2 ± 0.2 70.6 ± 4.2 n/d
kcat/Inline graphic, min−1 mM−1 0.29 ± 0.02 0.010 ± 0.002 (8.0 ± 0.7) × 10−4 n/d

n/d, not determined.