A. The chemical structures of the side chains of the Thr, Ala, Ser, Val, Ile and Phe residues and representative traces for the current responses evoked by Zn2+ (10 mM) in ZACThr128-, ZACAla128-, ZACSer128-, ZACVal128-, ZACIle128- and ZACPhe128-expressing oocytes. B. Averaged current amplitudes evoked by Zn2+ (10 mM) in ZACThr128-, ZACAla128-, ZACSer128-, ZACVal128, ZACIle128- and ZACPhe128-expressing oocytes (mean ± S.E.M., n = 5–8) (left), and averaged concentration-relationships displayed by Zn2+ at ZACThr128, ZACSer128 and ZACVal128 (means ± S.E.M., n = 5–8) (right). C. Averaged current amplitudes evoked by H+ (pH 4.0) in ZACThr128-, ZACSer128-, ZACVal128, and ZACPhe128-expressing oocytes (mean ± S.E.M., n = 6–8). A–C. All oocytes were injected with 1.84 ng cRNA of the respective ZAC subunits.