Fig. 2.
A and B, Representative KATP currents recorded in response to successive voltage ramps from −110 to +100 mV in an inside-out patch excised from a Xenopus oocyte coexpressing the indicated homozygous KATP channels in the absence (A) and presence (B) of Mg2+. The dashed line indicates the zero current level. C and D, Mean relationship between [ATP] (C) or [MgATP] (D) and KATP conductance (G), expressed relative to the conductance in the absence of nucleotide (Gc), for Kir6.2/SUR1 (WT, black filled circles) and homKir6.2-28Δ32/SUR1 (hom28Δ32, unfilled circles) channels. The lines are the best fit of the Hill equation to the mean data: panel C, WT, IC50 = 5 μM, n = 9; hom28Δ32, IC50 = 16 μM, n = 10. Panel D, WT, IC50 = 13 μM, n = 6; hom28Δ32, IC50 = 89 μM, n = 5. Figures are derived from the fit of the mean data.
