Chloride efflux in K562 clones at 20°C. The gradients of linear regression lines are equivalent to efflux rate constants (^ok_Cl−). r2 values are K562/B3 clone 1 − DNDS, .97; K562/B3 clone 1 + DNDS, .96; K562/pBp − DNDS, .98; K562/pBp + DNDS, .88. The rate constant for band 3–mediated efflux in K562/B3 clone 1 was calculated as the difference between the rate constants for K562/B3 clone 1 − DNDS and K562/pBp − DNDS.