Fig. 6. Dissociation of the V-type H⁺ ATPase into V₁ and V₀ complexes. (A) The intact holoenzyme hydrolyzes ATP, transports H⁺, and generates voltage across the membrane; (B) intestinal inactivity during molt or starvation in caterpillars and glucose deprivation in yeasts causes the holoenzyme to dissociate. Concomitantly, ATP hydrolysis and proton transport collapse and membrane voltage goes to zero. (Adapted from Vitavska, 2005.)