TABLE 3.
l-Glutaminase kinetic parameters for ErA wild type and select mutants
N.D., not determined.
| Enzyme | kcat | Km | kcat/Km | kobs at 1 mm | kobs at 0.5 mm | Specific activitya |
|---|---|---|---|---|---|---|
| s−1 | mm | s−1mm−1 | s−1 | s−1 | IU/mg | |
| ErA-WT | 26.84 ± 0.26 | 0.36 ± 0.02 | 74.56 | 19.22 | 15.87 | 45.68 ± 0.44 |
| ErA-E63Q | 8.33 ± 0.16 | 3.86 ± 0.23 | 3.68 | 2.16 | 0.74 | 14.17 ± 0.27 |
| ErA-A31I/E63Q (DM1) | 6.01 ± 0.13 | 2.73 ± 0.20 | 3.33 | 2.20 | 0.83 | 10.22 ± 0.22 |
| ErA-E63Q/S254N (DM2) | 2.93 ± 0.03 | 15.80 ± 0.30 | 0.19 | 0.18 | 0.11 | 4.98 ± 0.05 |
| ErA-E63Q/S254Q (DM3) | 7.17 ± 0.64 | 84.04 ± 12.15 | 0.09 | 0.19 | 0.02 | 12.17 ± 1.19 |
| ErA-A31I/E63Q/S254N (TM1) | 5.60 ± 0.20 | 28.20 ± 2.30 | 0.19 | 0.33 | 0.11 | 9.51 ± 0.34 |
| ErA-A31I/E63Q/S254Q (TM2) | 1.84 ± 0.11 | 47.46 ± 6.95 | 0.04 | N.D. | 0.01 | 3.12 ± 0.02 |
| EcA-WT | 0.89 ± 0.01 | 1.38 ± 0.09 | 0.64 | 0.36 | 0.22 | 1.53 ± 0.02 |
a 1 IU of enzyme is defined as the amount of enzyme used to produce 1 μmol of product in 1 min at 37 °C.