Ponceau S is a rapid and reversible stain for detecting protein bands on Western blot membranes and can be used with PVDF, nitrocellulose and cellulose acetate membranes. Microgram quantities of transferred protein can be detected with Ponceau‐S Stain, which generates reddish-pink protein bands with a clear background. The limit of detection for this stain is 100 ng BSA/ band transferred to nitrocellulose membranes.
This staining technique is reversible to allow further immunological detection. The limit of detection for this stain is 250 nanograms of protein after separation by electrophoresis in polyacrylamide gels and transferred to nitrocellulose membranes. Ponceau S is a negative stain that binds to the positively charged amino groups of the protein. It also binds non-covalently to non-polar regions in the protein. (Note: Ponceau S is not suitable for use with nylon membranes.)
The stain is useful because it does not have a deleterious effect on the sequencing of blotted polypeptides and the user can completely remove it from the protein bands by continued washing.