Table 1.

Kinetic parameters associated with the uptake of p-aminohippuric acid and acamprosate, substrates for OAT1, and of estrone-3-sulfate, a substrate for OAT3, in HEK293-Flp-In OAT1 and OAT3 cells, respectively. Data are reported as mean ± SEM of replicates in three cell passages obtained in ¹ Lab. 1 or ² Lab. 2.

Substrate	p-Aminohippuric Acid 2	Acamprosate 1	Estrone-3-Sulfate 2
Carrier	OAT1	OAT1	OAT3
Km (µM)	43 ± 13	698 ± 192	26 ± 6
Vmax (pmol∙mg protein−1∙min−1)	429 ± 39	1028 ± 99
Vmax (fmol∙cm−2∙min−1)			8.8 ± 0.7
CLT (cm/min)			5.6 × 10−9
CLT (µL∙mg protein−1∙min−1)	10	1.5
P (µL∙mg protein−1∙min−1)		0.35 ± 0.04

V_max is the OAT1-mediated maximal uptake rate, K_m is the Michaelis constant (calculated only from the saturable uptake component); CL_T is the carrier-mediated clearance (V_max/K_m); P is the contribution of passive diffusion and potential effects from isotope dilution or non-specific cell binding.