Testing Urine for Protein and Glucose Glycosylation is the enzymatic process that links saccharides to produce glycans, attached to proteins, lipids, or other organic molecules. This enzymatic process produces one of the fundamental biopolymers found in cells (along with DNA, RNA, and proteins). Glycosylation is a form of co-translational and post-translational modification. Glycans serve a variety of structural and functional roles in membrane and secreted proteins.[1] The majority of proteins synthesized in the rough ER undergo glycosylation. It is an enzyme-directed site-specific process, as opposed to the non-enzymatic chemical reaction of glycation. Glycosylation is also present in the cytoplasm and nucleus as the O-GlcNAc modification. Five classes of glycans are produced: N-linked glycans attached to a nitrogen of asparagine or arginine side chains, O-linked glycans attached to the hydroxy oxygen of serine, threonine, tyrosine, hydroxylysine, or hydroxyproline side chains, or to oxygens on lipids such as ceramide; phospho-glycans linked through the phosphate of a phospho-serine; C-linked glycans, a rare form of glycosylation where a sugar is added to a carbon on a tryptophan side chain, and glypiation which is the addition of a GPI anchor which links proteins to lipids through glycan linkages.  Rating 0/10 Views 264 Duration 00:30