TABLE 3.
Substrate specificity of recombinant prephenate aminotransferases
Values given are the average of at least three independent determinations. The difference in each set of data was <10%. All aminotransferases were tested in the presence of 25 mm glutamate and up to a 500 μm concentration of the indicated ketoacids, except for S-DAPAT activity, which was tested in the presence of 5 mm S-DAP and up to 500 μm α-ketoglutarate. 0, no activity detected. OAA: oxaloacetate; 4-MOV: 4-methyl-2-oxovalerate; PP: phenylpyruvate.
| OAA | 4-MOV | S-DAP | PP | HPP | |
|---|---|---|---|---|---|
| AAT/PAT | |||||
| Rme_Q02635 | kcat = 205 s−1; Km = 17 μm | 0 | 0 | 0 | 0 |
| Rsp_A3PMF8 | kcat = 150 s−1; Km = 27 μm | 0 | 0 | 0 | 0 |
| Neu_Q82WA8 | kcat = 35 s−1 ; Km = 33 μm | 0 | 0 | 0 | 0 |
| BCAT/PAT | |||||
| Syn_P54691 | 0 | kcat = 70 s−1; Km = 45 μm | 0 | kcat = 18 s−1; Km = 400 μm | kcat = 20 s−1; Km = 450 μm |
| Sco_Q3AJX2 | 0 | kcat = 130 s−1 ; Km = 27 μm | 0 | 0 | kcat = 25 s−1 ; Km = 250 μm |
| S-DAPAT/PAT | |||||
| Sav_Q82IK5 | 0 | 0 | NDa | 0 | 0 |
| Mtu_O50434 | 0 | 0 | ND | 0 | 0 |
| Neu_Q82S89 | 0 | 0 | ND | 0 | 0 |
a ND, the capacity of S-DAPAT from S. avermitilis (Sav_Q82IK5), M. tuberculosis (Mtu_O50434), and N. europaea (Neu_Q82S89) to catalyze the transamination of α-ketoglutarate with S-DAP as amino donor was confirmed by spectrophotometry and HPLC (see Fig.6), but the kinetics parameters were not determined.