Special Glycoproteins

Most proteins are glycoproteins; proteins covalently linked to carbohydrates. More frequently, the protein portion of a glycoprotein accounts for the majority of the total molecular weight and is mainly responsible for function. In the case of a mucin, however, the carbohydrate may account for the majority of the molecular weight and assume major biological functions. Fetuin is another highly glycosylated protein found in plasma that is routinely used as a positive control for studying protein glycosylation.