Improved method for silver staining of glycoproteins in thin sodium dodecyl sulfate polyacrylamide gels

A method for detection of glycoproteins in thin sodium dodecyl sulfate polyacrylamide gels was developed by a combination of (i) initial periodic acid oxidation/Alcian blue staining and (ii) subsequent staining with silver nitrate. The procedure allowed detection of as little as 1.6 ng of alpha 1-acid glycoprotein and 8-40 ng of a polydisperse mucin sample, which is at least 10 times more sensitive than previously published methods. The method should be very useful for assessment of sample purity and detection of glycoproteins in dilute mixed samples.