Figure 3.

Kinetics of MgATP-dependent, uncoupler-insensitive ¹⁰⁹Cd·GS₂ (HMW-¹⁰⁹Cd·GS; A) and ¹⁰⁹Cd·GS (LMW-¹⁰⁹Cd·GS; B) uptake. S-(2,4-dinitrophenyl)glutathione (DNP-GS) was added at the concentrations (μM) indicated to DTY165 membranes (•, ○, ▪, □, ▵) or DTY167 membranes (⋄). A secondary plot of the apparent Michaelis constants for Cd·GS₂ uptake (K_m^app/Cd·GS₂) as a function of DNP-GS concentration is shown (C). The kinetic parameters for Cd·GS₂ transport by DTY165 membranes were K_m, 39.1 ± 14.1 μM, V_max, 157.2 ± 30.4 nmol/mg/10 min, and K_i(DNP-GS), 11.3 ± 2.1 μM. Kinetic parameters were computed by nonlinear least squares analysis (14). Values shown are means ± SE (n = 6).