TABLE 2.
Substrate specificity of d-AAT from Geobacillus toebii SK1
| Amino donor | Relative activity (%)a | Amino acceptors | Relative activity (%)a |
|---|---|---|---|
| d-Alanine | 100 | α-Ketoglutarate | 100 |
| d-α-Aminobutyrate | 89 | α-Ketobutyrate | 110 |
| d-Aspartate | 70 | α-Ketoisovalerate | 13 |
| d-Serine | 12 | Phenyl pyruvate | 2 |
| d-Asparagine | 11 | ||
| d-Norvaline | 8.2 | ||
| d-Tryptophan | 4.9 | ||
| d-Valine | 1.9 | ||
| d-Histidine | 1.9 | ||
| d-Threonine | 0.9 | ||
| d-Methionine | 0.7 |
a
The relative activity was calculated by analyzing the formation of d-glutamate from α-ketoglutarate using an automatic amino acid analyzer. The amino acceptor specificity was assayed by measuring the formation of pyruvate from d-alanine as an amino group donor. All reactions were carried out at 50°C in the standard assay mixture containing 10 mM substrates. Inert amino acceptors included benzyl formate, hydroxylphenyl pyruvate, and indole pyruvate.