Table 3.
Kinetic properties of GabT
| Enzyme | Substrate | Km (μM) | kcat (s−1) | kcat/Km (s−1 M−1) |
|---|---|---|---|---|
| GabT | GABAa | 399 ± 40 | 0.48 ± 0.021 | 1.2 103 |
| 2-Oxoglutarateb | 58 ± 7 | 8.3 103 | ||
| DAPa | 4356 ± 1014 | 0.22 ± 0.016 | 5.1 101 |
Abbreviation: GABA, gamma-aminobutyric acid.
Aminotransferase activities were determined in the presence of 200 μM pyridoxal phosphate, 2 U of l-glutamate dehydrogenase, and 5 mM NAD+ in a spectrophotometric coupled assay by measuring the formation of NADH, as described under the Experimental procedures section. Values are the average of three replicates.
a
2-Oxoglutarate concentration was 500 μM.
b
GABA concentration was 4 mM.