glycoconjugués

Glycoconjugates, or glycoconjugés in French, are molecules in which carbohydrates are covalently linked to non-carbohydrate moieties, typically proteins or lipids. They are abundant on cell surfaces and in the extracellular matrix and play diverse roles in biology.

Major classes include glycoproteins, glycolipids, and proteoglycans. Glycoproteins bear oligosaccharide chains attached to protein backbones, primarily via N-linked (asparagine) or O-linked (serine/threonine) glycosylation. Glycolipids have carbohydrate head groups attached to lipid backbones, commonly ceramide with glycosphingolipids. Proteoglycans consist of a core protein with one or more sulfated glycosaminoglycan (GAG) chains. Some proteins are anchored to membranes via glycosylphosphatidylinositol (GPI) anchors.

Biosynthesis occurs mainly in the endoplasmic reticulum and Golgi apparatus; assembly lines of glycosyltransferases sculpt the carbohydrate chains. N-linked glycans start in the ER with a preassembled dolichol-linked oligosaccharide, while O-linked glycosylation occurs in the Golgi. GAG chains are assembled on serine residues of core proteins and are later sulfated and epimerized.

Functions of glycoconjugates include mediating cell–cell recognition, adhesion, and signaling; modulating protein folding, stability, and half-life; and participating in immune responses and host–pathogen interactions. Glycan epitopes act as molecular recognition determinants in processes such as fertilization and embryonic development. Conjugate vaccines use polysaccharide or glycopeptide antigens linked to a protein carrier to enhance immunogenicity.

Research and applications span glycomics, mass spectrometry, and glycan arrays to study glycoconjugates, with relevance to diagnostic biomarkers, therapeutic targets in cancer and infectious diseases, and roles in biomaterials and drug delivery.