PMC

Ghosts were prepared to contain, during the uptake measurement, 85 mM K⁺, 2 mM ATP, 0.1 mM Mg²⁺ and the indicated concentrations of dimethonium or ethylenediamine. When the concentration of the inhibitor was less than 40 mM, it was replaced with choline chloride to maintain constant osmolality. Ghosts were resealed by incubation for 45 min at 37 °C and 472 mosmol (kg H₂O)⁻¹. K⁺ uptake was measured over a 45 min period in buffered choline chloride or choline nitrate solution containing 2 mM K⁺ and set at 295 mosmol (kg H₂O)⁻¹ so that ghost volume during the uptake measurement was 1.6 times its value at resealing. In solutions to which ghosts containing ethylenediamine were added, ethylenediamine at the concentrations indicated replaced an equal amount of choline. Curves are v = V_m/(1 +[I]/K_I). For the experiment with dimethonium, V_m was 4.6 mmol (l ghosts)⁻¹ h⁻¹ and K_I was 1221 mM. For the experiment with ethylenediamine, V_m was 3.8 mmol (l ghosts)⁻¹ h⁻¹ and K_I was 3.8 mM.

(A) Partial ¹H NMR spectra of C-CNC and ethylenediamine in D₂O before (top) and after (bottom) reaction, (B) TEM images of aqueous solution of C-CNC and ethylenediamine before and (C) after reaction, scale bars = 10 nm, (D) Optimized conformation of C-CNC/EDA, red sticks = oxygen atoms, gray sticks = carbon atoms.