Advantages of preelectrophoretic conjugation of polypeptides with fluorescent dyes.

A rapid simple procedure is described for the conjugation of proteins, glycoproteins, and peptides with the fluorescent dye fluorescein isothiocyanate during the time required to polymerize a polyacrylamide gel. Such conjugation does not perturb the electrophoretic mobility of the polypeptides in detergent containing gels. The location of polypeptide . dye conjugate is evident by inspection immediately upon removal of a gel from an electrophoresis cabinet avoiding the time required for postelectrophoretic staining and destaining procedures. The sensitivity of detection of polypeptide . fluorescein conjugates is at least equivalent to that obtained using Coomassie blue.