Detection of 6-His-tagged Protein by Western Blot. Samples: 200, 100, or 50 ng of E. coli whole cell lysate expressing a multi-tag fusion protein.     Antibodies: Affinity-purified, biotin-conjugated, goat anti-6-His antibody A190-113B used for WB at 0.04 ug/ml (1:25,000).   Detection: Streptavidin-HRP (0.1 ug/ml) and chemiluminescence with an exposure time of 10 seconds.