Mechanism of reversible fluorescent staining of protein with epicocconone

[reaction: see text] Epicocconone is the active ingredient in Deep Purple Total Protein Stain and responsible for the apparent noncovalent staining of proteins in polyacrylamide gel and electroblots. Reaction of epicocconone with amines has shown that epicocconone reacts reversibly with primary amines to produce a highly fluorescent enamine that is readily hydrolyzed by base or strong acid such as in conditions used in post-electrophoretic analysis such as peptide mass fingerprinting or Edman degradation.