SITE-SPECIFIC PROTEIN GLYCOSYLATION

Most cell-surface and secreted proteins derived from eukaryotic cells are glycosylated, with attachment of carbohydrates occurring usually at several sites along the polypeptide chain. Synthesis of these carbohydrates and their attachment is a complex process involving a large number of intracellular enzymes and a complex topological arrangement of organelles, which leads to the attachment of unique sets of carbohydrates at each glycosylated site. The factors which influence which precise set of carbohydrates, from those which a cell is capable of synthesizing, are attached at a particular site depends on the polypeptide sequence, the cellular genotype and phenotype, and the extracellular hormonal and metabolic environment. These factors will be reviewed in this article.