Table 1.
Kinetic parameters of purified point mutants of 37-kDa PTP1B assessed with pTyr-RCML as substrate
| Enzyme | Vmax, nmol/min/mg | Km, nM | kcat, min−1 |
|---|---|---|---|
| Wild type | 60,200 | 102 | 2244 |
| Tyr-46 → Ser | 4,120 | 1700 | 154 |
| → Leu | 4,160 | 1700 | 155 |
| Glu-115 → Ala | 5,700 | 45 | 212 |
| → Asp | 5,900 | 20 | 220 |
| Lys-116 → Ala | 68,600 | 150 | 2557 |
| Lys-120 → Ala | 19,000 | 80 | 708 |
| Asp-181 → Ala | 0.61 | ≤126 | 0.023 |
| → Glu | 97 | 10 | 3.6 |
| His-214 → Ala | 700 | 20 | 26 |
| Cys-215 → Ser | No detectable activity | ||
| Arg-221 → Lys | 11 | 80 | 0.41 |
| → Met | 3.3 | 1060 | 0.12 |
| Gln-262 → Ala | 720 | 9 | 27 |