Glýkólíseringu

Glýkólíseringu (glycosylation) is a biochemical process in which carbohydrate groups are covalently attached to proteins or lipids. It is a common post-translational modification that occurs primarily in the endoplasmic reticulum and the Golgi apparatus and is essential for proper folding, stability, distribution, and function of many biomolecules.

Two major types are N-linked glycosylation and O-linked glycosylation. N-linked glycosylation attaches an oligosaccharide to the amide nitrogen of asparagine within the consensus sequence N-X-S/T, beginning in the endoplasmic reticulum with the assembly of a dolichol-linked precursor and transfer to the growing polypeptide by oligosaccharyltransferase, followed by extensive processing in the Golgi. O-linked glycosylation attaches sugars to the oxygen of serine or threonine residues and occurs mainly in the Golgi, with diverse cores and termini that vary by organism and tissue.

Functions include facilitating proper protein folding and quality control, increasing stability and solubility, guiding trafficking and localization, and mediating cell–cell and cell–matrix interactions. Glycan structures influence receptor binding, immune recognition, and the circulatory half-life of therapeutic proteins. Abnormal glycosylation is linked to diseases such as congenital disorders of glycosylation (CDG) and is frequently observed in cancer and inflammatory conditions.

Analytical and applied aspects: glycoproteomics uses mass spectrometry, chromatography, or lectin-based assays to characterize glycan structures. In biotechnology, glycoengineering aims to modify glycosylation to improve efficacy and safety of biopharmaceuticals.