Figure 2.

Deuterium NMR spectra (recorded at 0°C) of [steroid-²H₆]ODA (IV) and [rhamnose-²H₆]ODA (V) in solid powder form (A) and when added to renal Na⁺/K⁺-ATPase membranes in molar equivalence to the digitalis sites (B). The spectrum after addition of an excess of ouabain is shown (Inset). The spectrum of IV in the membrane preparation (B Left) was simulated (using algorithms described in ref. 26) by superposition of a Lorenztian line shape and an axially symmetrical powder pattern with a residual quadrupole splitting of 17 kHz. The powder component represented >70% of the total signal.