Which dye may be used for staining protein bands after electrophoresis?

Which dye may be used for staining protein bands after electrophoresis?

• A. Fat Red 7B
• B. Sudan Black B
• C. Ponceau S
• D. Oil Red O

Answer: (C)

Visualizing protein bands after electrophoresis relies on a dye that binds to proteins and can be removed easily so downstream detection isn’t hindered. Ponceau S fits this role well because it non-specifically binds to the proteins on membranes or gels, giving a clear red stain that shows all transferred proteins. Crucially, this stain is reversible, so it can be washed away with water or mild buffers, leaving the proteins ready for antibody-based detection in Western blotting. The other dyes are lipid stains and target fats rather than proteins, so Fat Red 7B, Sudan Black B, and Oil Red O won’t reliably highlight protein bands after electrophoresis.

Visualizing protein bands after electrophoresis relies on a dye that binds to proteins and can be removed easily so downstream detection isn’t hindered. Ponceau S fits this role well because it non-specifically binds to the proteins on membranes or gels, giving a clear red stain that shows all transferred proteins. Crucially, this stain is reversible, so it can be washed away with water or mild buffers, leaving the proteins ready for antibody-based detection in Western blotting. The other dyes are lipid stains and target fats rather than proteins, so Fat Red 7B, Sudan Black B, and Oil Red O won’t reliably highlight protein bands after electrophoresis.