Table 1. Transport kinetic parameters of Oatp4c1-mediated E3S transport at pH 4.5, 5.5 and 7.4 (mean ± S.E.).

	pH 4.5	pH 5.5	pH 7.4
Tmax [(pmol/min )/mg protein]	612.6±109.7*	484. 0±50.4***	129.3±11.0**
S50 [µM]	60.5±22.7	49.3±8.8	21.5±3.6
n, Hill Coefficient	1.1±0.2	1.5±0.2	2.6±1.0

The parameters were estimated by fitting a sigmoid-E_max model to the data. Statistical analysis was performed by two-way ANOVA with Bonferroni post-hoc test for all pairwise comparisons. *, **, *** p<0.05 indicate significant differences between pH 4.5 and 5.5, pH 4.5 and 7.4, and pH 5.5 and 7.4, respectively.