glükoproteini

Glycoproteins are a class of proteins that have carbohydrate chains (glycans) covalently attached to them. This attachment process, known as glycosylation, is a crucial post-translational modification that occurs in the endoplasmic reticulum and Golgi apparatus of eukaryotic cells. The structure of the glycan chains can vary significantly, from simple branched sugars to complex, multi-antennal structures.

Glycoproteins play diverse and essential roles in biological systems. They are key components of cell membranes, where they act as receptors, adhesion molecules, and antigens. The carbohydrate portions of glycoproteins are often involved in cell-cell recognition, immune responses, and cellular signaling. For instance, the ABO blood groups are determined by the specific carbohydrate structures found on the surface glycoproteins of red blood cells.

Many secreted proteins are also glycoproteins, including hormones like erythropoietin, enzymes, and antibodies. In these cases, glycosylation can influence protein folding, stability, solubility, and biological activity. The presence or absence of specific glycosylation patterns can also be indicative of disease states, making glycoproteins important biomarkers in diagnostics. The study of glycoproteins is known as glycobiology.