Table V.
Influence of various phosphatase inhibitors on the catalytic activity of SynPTP.
| Inhibitors | Concentration (mM) | Specific activity (pmole/min/mg) |
|---|---|---|
| Control | 0 | 560 ± 22 |
| Ammonium molybdate | 5 | ND |
| Sodium orthovanadate | 5 | 44 ± 2.5 |
| Zinc sulphate | 5 | ND |
| Sodium sulphate | 5 | 640 ± 35 |
| Sodium fluoride | 5 | 680 ± 14 |
| Okadaic acid | 0.005 | 720 ± 22 |
All assays were carried out as described in the ‘Materials and Methods’ section. RCML (32P-Tyr) was used as substrate at a final concentration of 2 µM of protein bound phosphate. Potential inhibitors were present at the indicated final concentration. The enzyme activity is reported relative to that observed with RCML(32P-Tyr) in the absence of any inhibitor, which was 560 pmol/min/mg, and set equal to 100%. ND represents not detectable, <2%, or 12 pmol/min/mg.