TABLE 1.
Kinetic parameters for the enzymes of the l-carnitine metabolic pathway
| Enzyme | Substrate | Km (μM)a | kcat (s−1)a | kcat/Km (s−1 · M−1)a |
|---|---|---|---|---|
| BcoA/B (Smc01640) | GBBb | 1,120 ± 303 | 25.3 ± 1.9 | 2.3 × 104 |
| ATPc | 96 ± 9 | 2.6 × 105 | ||
| CoAd | 45 ± 7 | 5.6 × 105 | ||
| Crotonobetaineb | 3,000 ± 693 | 0.05 ± 0.004 | 17 | |
| BcoC (Smc01639) | γ-Butyrobetainyl-CoAe | 4.1 ± 1.7 | 1.8 ± 0.12 | 4.4 × 105 |
| FADf | 0.8 ± 0.2 | 2.3 × 106 | ||
| BcoD (Smc01641) | Crotonobetainyl-CoA | 20.5 ± 2.1 | 8.5 ± 0.10 | 4.2 × 105 |
| CDH thioesterase (Smc01638) | l-Carnitineg | 940 ± 68 | 6.2 ± 0.10 | 6.6 × 103 |
| NAD+h | 154 ± 13 | 5.1 ± 0.10 | 3.3 × 104 | |
| l-Carnitinyl-CoA | 12 ± 3 | 0.9 ± 0.1 | 7.5 × 104 | |
| Betainyl-CoA | 12 ± 1 | 142.3 ± 3.0 | 1.2 × 107 | |
| BKACE (Smc01637) | Dehydrocarnitinei | 13 ± 2 | 0.24 ± 0.01 | 1.8 × 104 |
| Acetyl-CoAj | 118 ± 18 | 2.0 × 103 |
a
Values correspond to the averages from two replicates.
b
ATP and CoA concentrations were 2 mM and 200 μM, respectively.
c
GBB and CoA concentrations were 5 mM and 200 μM, respectively.
d
GBB and ATP concentrations were 5 mM and 2 mM, respectively.
e
FAD concentration was 50 μM.
f
γ-Butyrobetainyl-CoA concentration was 80 μM.
g
NAD+ concentration was 1.5 mM.
h
l-Carnitine concentration was 10 mM.
i
Acetyl-CoA concentration was 1.5 mM.
j
Dehydrocarnitine concentration was 100 μM.