Parameters of initial uptake of AZT by TR-TBT 18d-1 cells obtained by fitting to the Michaelis-Menten equation
Km, Vmax, and kns are transport affinity, maximum transport velocity, and nonsaturable transport clearance, respectively. Vmax/Km indicates intrinsic transport clearance. Data are presented as mean ± S.D. estimated by nonlinear least-squares regression analysis using the MULTI program.