Table 1. Comparison of the substrate-specificity of wild-type MDH, MDH-GOX2, MDH G81A and MDH-GOX2 G81A.
Steady-state kinetic parameters were obtained at 293K using (R,S)-mandelate as substrate. Assays were performed in 0.1M potassium phosphate pH 7.5 with 150mM DCPIP, 1mgml1 BSA and 1mM phenazine methosulfate.
| Wild-type MDH | MDH G81A | MDH-GOX2 | MDH-GOX2 G81A | |||||
|---|---|---|---|---|---|---|---|---|
| Substrate | k cat (s1) | K m (mM) | k cat (s1) | K m (mM) | k cat (s1) | K m (mM) | k cat (s1) | K m (mM) |
| Mandelate | 350 10 | 0.24 0.02 | 15.2 0.3 | 0.24 0.02 | 205 4 | 0.09 0.01 | 2.3 0.07 | 0.04 0.01 |
| 3-Indolelactate | 1.0 0.01 | 0.9 0.1 | 0.3 0.01 | 0.17 0.01 | 3.9 0.07 | 0.64 0.04 | 1.4 0.05 | 0.13 0.02 |
| 2-Hydroxyoctanoate | 0.5 0.06 | 0.8 0.1 | 0.3 0.01 | 0.14 0.01 | 1.0 0.01 | 0.29 0.01 | 0.42 0.02 | 0.57 0.01 |