Table 2.
Substrate specificities of pNBE and selected variants.
| Enzyme | Substrate | kcat (1/min) | Km (mM) | kcat/Km (1/min*mM) |
|---|---|---|---|---|
| WT | pNPA | 370 ± 30 | 1.2 ± 0.3 | 300 ± 80 |
| pNPB | 1100 ± 40 | 0.08 ± 0.01 | 14000 ± 2000 | |
| A107H | pNPA | 130 ± 10 | 5.6 ± 0.7 | 23 ± 3 |
| pNPB | 520 ± 20 | 0.12 ± 0.02 | 4300 ± 700 | |
| A107H/A190C | pNPA | 70 ± 10 | 0.9 ± 0.4 | 70 ± 30 |
| pNPB | 7 ± 1 | 0.3 ± 0.1 | 20 ± 10 | |
| A107H/A400T | pNPB | 460 ± 10 | 0.12 ± 0.02 | 3800 ± 600 |
| A107H/A400V | pNPB | 510 ± 30 | 0.17 ± 0.03 | 3000 ± 600 |
| BChE Ω Loop Mutant with A107H | pNPA | 185 ± 6 | 1.6 ± 0.1 | 116 ± 8 |
pNPA (pNP-acetate) and pNPB (pNP-butyrate) assays were run in 50 mM HEPES pH 7.0, 150 mM NaCl, 22 ± 3°C. All enzymes had the N-terminal His-tag.