Table 1.
Enzyme | Substrate | Apparent Km (mM) | Specific activity (µmol min–1 mg–1) | kcat (s–1) | kcat/Km (s–1m M–1) |
rAroAT II | Phenylalanine | 1.3 | 1600 | 1200 | 923 |
Tyrosine | 2.6 | 1560 | 1130 | 434 | |
Tryptophan | 3.4 | 1960 | 1420 | 418 | |
α-Ketoglutarate | 0.9 | ||||
rAspAT | Aspartate | 4.2 | 158 | 105 | 25 |
α-Ketoglutarate | 0.46 |
1 For the amino acids, 5 mM α-ketoglutarate was used as the amino acceptor. For α-ketoglutarate, 20 mM phenylalanine or aspartate was used as the amino donor. The AspAt was assayed at 50 °C and the AroAT II was assayed at 80 °C.