Specificity of rabbit ZnT-1 antibody. Membrane proteins (100 μg) from either rat intestinal mucosa (A) or liver (B) were resolved on a 10% SDS/PAGE gel and transferred to nitrocellulose. Blots were then probed with the indicated reagent. PIS, preimmune rabbit serum, 1:500 dilution; IS, whole immune serum, 1:500 dilution; and, prepared as described in Materials and Methods, IgG, total IgG fraction, 50 μg/ml; AP, affinity-purified antibody, 2.5 μg/ml; and FT, unbound antibody fraction from affinity purification, 50 μg/ml. Blots were incubated with 2° Ab-horseradish peroxidase conjugate and then visualized with enhanced chemiluminescence. The migration of prestained molecular mass markers is given on the left. Location of ZnT-1 is shown by an arrow.