1 - The Chemistry of Glycoproteins

Abstract

This chapter reviews some aspects of the general chemistry and metabolism of glycoproteins. A protein containing a single covalently linked monosaccharide can be considered to be a glycoprotein. A protein of the molecular weight of serum albumin containing a single molecule of hexose would have a carbohydrate content of 0.28%. However, usually glycoproteins contain more than this amount of carbohydrate. The carbohydrate in glycoproteins may occur in a single relatively large oligosaccharide, or as a large number of relatively small oligosaccharides linked to the peptide chain. Most glycoproteins contain carbohydrate units of only one structural pattern. However, a few proteins have oligosaccharide chains of more than one type. These include thyroglobulin that contains one type of oligosaccharide comprised of sialic acid, galatose, acetyl glucosamine, and mannose, and another containing only mannose and acetyl glucosamine. The most unique structural feature of glycoproteins is the attachment of carbohydrate to the peptide chain.