Fig. 8. Rescue of V-ATPase activity by vha55 and VMA2 constructs. V-ATPase activities were measured as V_max in yeast vacuole preparations. Black bars, wild-type, vma2 and rescued yeast; empty bars, vma2 yeast rescued with vha55 cDNA mutated with SzA defects. Data are mean ± s.e.m. of assays on three independent cultures, and are expressed as a percentage relative to wild-type yeast: the average V_max of control preparations was 2.3±0.5 µmol Pi/minute/mg protein, comparable with values reported by others (Curtis et al., 2002; MacLeod et al., 1998).