Table 1.
Specific ITP/IDP hydrolysis activity in crude-cell extracts prepared from embryos and immortalized MEFs
| Isolate no. 1 |
Isolate no. 2 |
||||
|---|---|---|---|---|---|
| Cell extract | Substrate | Specific activity (u/µg) | SD | Specific activity (u/µg) | SD |
| Itpa+/+ embryo | ITP | 6.34 | 0.8 | 4.08 | 0.7 |
| Itpa+/+ embryo | IDP | 0.84 | 0.2 | 1.26 | 0.4 |
| Itpa+/+ iMEF | ITP | 6.42 | 0.9 | 7.24 | 1.0 |
| Itpa+/+ iMEF | IDP | 3.49 | 0.5 | 3.68 | 0.4 |
| Itpa−/– embryo | ITP | ND | ND | ||
| Itpa−/– embryo | IDP | 0.86 | 0.3 | 1.85 | 0.4 |
| Itpa−/– iMEF | ITP | 1.09 | 0.1 | 1.36 | 0.3 |
| Itpa−/– iMEF | IDP | 5.90 | 0.5 | 7.85 | 1.5 |
As a measure,1 unit (u) was defined as the level of activity producing 1 pmol of IMP at 30°C for 1 min with 0.2 mM ITP/IDP, pH = 8.0, n = 3. Key: ND, not detected; iMEFs, immortalized MEFs.