Table 3.
HPRT and APRT enzyme activities in HPRT-deficient MN9D sublines and their transfectants
| Cell line | HPRT | % control | APRT | % control |
|---|---|---|---|---|
| MN9D parent | 0.8 | 100 | 7.3 | 100 |
| AG6 | 0 | 0 | 10.7 | 146.6 |
| AG6 transf | 1.5 | 176.5 | 15.5 | 212.3 |
| AG8 | 0 | 0 | 7.4 | 121.9 |
| AG8 revert | 1.2 | 135.3 | 11.9 | 101.4 |
| AG10 | 0 | 0 | 11.9 | 163.0 |
| AG10 transf | 2.6 | 309.4 | 3.0 | 40.5 |
| TG2 | 0 | 0 | 14.9 | 204.1 |
| TG2 transf | 8.0 | 941.2 | 7.3 | 100.0 |
| TG3 | 0.1 | 7.1 | 5.2 | 71.2 |
| TG3 transf | 0.5 | 55.3 | 3.2 | 43.8 |
Results show enzyme activity expressed as nmol/mg protein per min, and percent of control. Each value was determined from a kinetic assay with five time points. Four of the lines in which HPRT was restored were found to be transfectants expressing the human HPRT mRNA (transf), while one was found to be a spontaneous revertant expressing the mouse HPRT mRNA (revert).