A chemical method for the deglycosylation of proteins

A simple and rapid chemical method for the deglycosylation of glycoproteins has been developed. The method involves the incubation of protein with trifluoromethanesulfonic acid at 0 °C from 0.5 to 2 h followed by the neutralization of the acid with aqueous pyridine at -20 °C. The method has been applied effectively to fetuin, ovine submaxillary mucin, ovine lutropin, and human choriogonadotropin. In 1 h almost all of N- and O-linked carbohydrates from ovine lutropin and human choriogonadotropin, with the exception of the linkage N-acetylglucomsamine or N-acetylgalactosamine, were removed. Similarly, in 1 h all N-linked carbohydrates, excepting again the linkage sugar, in fetuin were degraded. Longer reaction times up to 2 h completely removed the O-linked carbohydrate chains from fetuin and ovine submaxillary mucin. The deglycosylated hormones thus prepared retained their immunological and biological activities.