Transport kinetics of [3H]GlySar uptake in P. pastoris cells expressing different mammalian species of Pept1 gene
Parameter estimates are expressed as means ± S.E. (n = 9). The data were fitted to eq. 1 using a weighting factor of unity. GlySar concentrations ranged from 0.005 to 10 mM.
| Parameter | Yeast Transformant | |||
|---|---|---|---|---|
| pPIC3.5K | pPIC3.5K-hPept1 | pPIC3.5K-mPept1 | pPIC3.5K-rPept1 | |
| Vmax, pmol · OD−1 · min−1 | N.A. | 24.7 ± 2.4 | 61.5 ± 1.7 | 88.8 ± 1.5 |
| Km, mM | N.A. | 0.86 ± 0.25 | 0.30 ± 0.03 | 0.16 ± 0.01 |
| Kd, μl · OD−1 · min−1 | 2.21 ± 0.14 | 2.21 ± 0.14 | 2.21 ± 0.14 | 2.21 ± 0.14 |
| Vmax/Km, μl · OD−1 · min−1 | N.A. | 28.7 | 205.0 | 555.0 |
| r2 | 0.894 | 0.933 | 0.950 | 0.934 |
| Gene copy numbera | 1.28 ± 0.01 | 1.05 ± 0.14 | 1.17 ± 0.23 | 0.97 ± 0.07 |
N.A., not applicable.
↵a Gene copy number was measured by real-time PCR using species-specific Pept1 gene primers and the ARG4 gene as a control; AOX1 gene primers were used for vector alone (Table 3).