Glycans in health and disease

Summary. If a cell would need to produce one specific protein for each biological function, there would probably be over a million different proteins. However, the actual number is much lower. To save energy, cells use different methods to modify proteins, thus repurposing them and enabling them to perform different functions. The most common modification is glycosylation, a process in which one or more (the same or different) monosaccharide units are enzymatically linked to a protein (or another biomolecule). Glycan synthesis is a complex and incompletely understood process in which different forms of various types of glycans are formed. A set of glycans present in one cell or an organism represents their glycome and is a reflection of the cellular conditions in a specific environment. Glycomes are very flexible entities that constantly change in response to physiological circumstances, thus reflecting the habits of an organism as well as the process of biological ageing. Even more interestingly, glycomes also change under specific and pathological conditions. Understanding how and why the glycome changes will help in design of new medical treatments for such pathological processes.