Metal binding to purified ZinT. A, purified recombinant ZinT (right lane) on an SDS-PAGE gel. Size markers (left lane) are shown in kDa. The elution profiles of ZinT and Zn2+ are from a PD-10 column following incubation of protein and metal ions. B, elution following incubation of 13.3 nmol of ZinT with no added metal. C–F, elution following incubation of 28.6 nmol of ZinT with 0.25, 0.5, 1, or 2 molar equivalents of Zn2+. Filled circles with solid line, ZinT; open circles with dashed line, Zn2+.