. Author manuscript; available in PMC: 2012 Oct 27.

Published in final edited form as: J Med Chem. 2011 Sep 22;54(20):7150–7164. doi: 10.1021/jm200739e

Table 2. Kinetic constants for hPCFT.

Kinetic constants for MTX (K_t and V_max) were determined with [³H]MTX by Lineweaver-Burke plots with R2/hPCFT4 cells, whereas K_i values were determined by Dixon plots with [³H]MTX as substrate and a range of inhibitor concentrations in R2/hPCFT4 cells. Results are presented as mean values ± standard errors from 3 experiments.

Substrate	Parameter	pH 5.5	pH 6.8

MTX^a	K_t (micromolar)	0.28 ± 0.02	4.52 ± 0.19
MTX^a	V_max (pmol/mg/min)	31.23 ± 4.31	13.72 ± 2.26
PMX^a	K_i (micromolar)	0.096 ± 0.012	1.54 ± 0.17
3	K_i (micromolar)	0.13 ± 0.01	1.82 ± 0.07
4^a	K_i (micromolar)	0.13 ± 0.01	1.95 ± 0.02

From Wang et al. (ref. 14).