Edward J. McGuire

BIOSYNTHESIS OF SUBMAXILLARY MUCINS

Publisher Summary This chapter discusses the biosynthesis of submaxillary mucins. Sugar additions are carried out by enzymes (glycosyltransferases), which add one sugar at a time to the nonreducing terminus of the incomplete oligosaccharide side chains. This is a non-template mechanism mediated by one enzyme for each linkage, that is, each glycosyltransferase is capable of forming one unique linkage with one sugar. Glycosyltransferases, as found in the cell, are membrane-bound enzymes. The glycosyltransferases can be grouped into families of enzymes based on the type of monosaccharide transferred. The individual members of a family of glycosyltransferases can be distinguished on the basis of the acceptor molecule specificity or by the linkage of the glycose unit to the acceptor molecule. The addition of carbohydrate to proteins is intimately connected to the process of secretion of macromolecules. The glycosyltransferases are grouped together in the cell as particulate complexes or as multiglycosyltransferase systems. The chapter describes the reactions involved in the biosynthesis of ovine and porcine submaxillary mucin.