TABLE 4.

Kinetic parameters of metformin uptake in HEK293 cells stably transfected with human OCT1 (reference) or its variants

Data were fit to a Michaelis–Menten equation. Results were expressed as nmol/mg protein/min. Data points represented the mean ± S.D. from triplicate wells in a representative experiment. The K_m and V_max values were determined from the fit of the data in Fig. 1B.

Kinetic Parameter	OCT1-ref	Q97K	P117L	R206C
Vmax (nmol/mg protein/min)	3.96 ± 0.44	3.47 ± 0.12	2.02 ± 0.27*	0.79 ± 0.15*
Km (mM)	1.18 ± 0.18	3.31 ± 0.69*	1.51 ± 0.15	1.31 ± 0.22

^* P < 0.05 versus OCT1-ref.