Cell Lines | MTX | 5-CHO-THF | 5-CH3-THF | Folic Acid | ||
---|---|---|---|---|---|---|
Kt | Vmax | Relative RFC1 Expression | Ki | Ki | Ki | |
μM | μM | |||||
L1210 | 7.0 (1) | 12 (1) | 1 | 5.6 (1) | 1.5 (1) | 260 (1) |
MTXrA-E45K | 0.43 | 1.5 (K t) (0.27) | 1.3 (0.87) | 34 (0.13) | ||
MTXrA-E45Q | 15.8 (2.3) | 23 (1.9) | 1.1 | 1.6 (0.28) | 0.6 (0.4) | 42 (0.16) |
MTXrA-E45R | 8.0 (1.1) | 5.3 (0.44) | 0.70 | 1.2 (0.21) | 1.4 (0.93) | 27 (0.1) |
MTXrA-E45D | 25 (3.6) | 4.5 (0.38) | 0.43 | 50 (8.9) | 4.3 (2.9) | 400 (1.5) |
MTXrA-E45L | 13 (1.8) | 15 (1.3) | 0.87 | 11.4 (2.0) | 6.5 (4.3) | 117 (0.45) |
MTXrA-E45W | 0.62 | 163 (29) | 15 (10) | 130 (0.5) |
MTX influx K t and V max (nmol/g of dry wt/min) values are the average of two experiments determined from nonlinear regression to the Michaelis-Menten equation. Folate influxK i values (μM) are the average of two experiments obtained from Dixon plot analysis based on inhibition of MTX influx. The numbers in parentheses are the ratio of parameters in transfectants to L1210 cells.