glycosylated

Glycosylated is an adjective used in biochemistry to describe a molecule that has one or more carbohydrate groups, or glycans, covalently attached. Commonly this refers to glycoproteins, but glycosylation also occurs on lipids and other molecules. In proteins, glycosylation is a major post-translational modification that influences folding, stability, distribution, and interactions. The two main types are N-linked glycosylation, where a glycan is attached to the amide nitrogen of asparagine, typically within the consensus sequence Asn-X-Ser/Thr, and O-linked glycosylation, where glycans attach to serine or threonine residues. N-linked glycosylation begins in the endoplasmic reticulum and is further processed in the Golgi apparatus; O-linked glycosylation occurs mainly in the Golgi.

Glycans also decorate lipids to form glycolipids and can anchor proteins to membranes via GPI anchors, or form proteoglycans when large glycosaminoglycan chains are attached to core proteins. The pattern of glycosylation can affect protein folding, proteolytic stability, serum half-life, and cell-cell recognition, with functional consequences in development, immunity, and disease. Aberrant glycosylation is associated with congenital disorders of glycosylation and with cancer and inflammatory conditions; changes in glycosylation are also exploited in biotechnology to improve therapeutic protein properties (glycoengineering).

Analytical methods include mass spectrometry, high-performance liquid chromatography, and lectin-based assays. The term glycosylated therefore describes molecules that carry glycan modifications, reflecting a dynamic and biosynthetically regulated layer of cellular function.