Practice question

Sensitivity differences among protein dyes determine detection limits in gels. Coomassie Brilliant Blue R-250 detects roughly 50 to 100 nanograms per band by binding electrostatically to basic and aromatic residues, suitable for routine quantification. Silver staining involves impregnation of gel with silver ions that bind to carboxyl, sulfhydryl and amino side chains, followed by reduction to metallic silver by formaldehyde, achieving 50 to 100-fold greater sensitivity down to 1 to 5 nanograms. Bromophenol blue merely tracks migration front, while ethidium bromide and SYBR Green intercalate nucleic acids, not proteins, limiting their utility.