TABLE 5

Transport kinetics of [3H]cefadroxil uptake in P. pastoris cells expressing different mammalian PEPT2 genes

Parameters are expressed as mean ± S.E. (n = 3). Following vector subtraction, the data were fit to a Michaelis-Menten equation using a weighting factor of unity. Cefadroxil concentrations ranged from 1 to 250 μΜ. Statistical analyses were performed using one-way analysis of variance followed by Tukey’s test. Parameters with common capital letters (i.e., A, B, or C) were not significantly different between genotypes.

Parameters (unit)Yeast Transformant
pPIC3.5KpPIC3.5K-hPEPT2pPIC3.5K-mPEPT2pPIC3.5K-rPEPT2
Vmax (pmol/OD/min)N.A.8.71 ± 0.37A0.22 ± 0.01B2.18 ± 0.08C
Km (μM)N.A.150.8 ± 11.8A15.6 ± 1.8B11.9 ± 1.5B
Vmax/Km (μl/OD/min)N.A.0.058 ± 0.005A0.014 ± 0.002B0.183 ± 0.024C
r20.9960.9890.9230.892
  • N.A., not applicable.