Sialihappoja

Sialihappoja, commonly known as sialic acids, are a diverse group of nine-carbon monosaccharides that are found on the surface of animal cells. They are characterized by a carboxyl group at position 1 and an amino group at position 2. The most prevalent sialic acid in vertebrates is N-acetylneuraminic acid (Neu5Ac), while N-glycolylneuraminic acid (Neu5Gc) is also found in many mammals, though not in humans due to a genetic mutation. Sialic acids are typically found as terminal residues of glycans, which are carbohydrate chains attached to proteins and lipids. This strategic placement on cell surfaces makes them crucial players in various biological processes.

The functions of sialic acids are extensive and varied. They play a significant role in cell-cell recognition and adhesion, influencing interactions between cells and their environment. Their negative charge can repel negatively charged molecules, contributing to the fluidity of cell membranes and protecting cells from pathogens. Sialic acids are also involved in immune responses, acting as ligands for immune receptors and influencing the behavior of immune cells. Furthermore, they are implicated in neurological functions, as they are abundant in the brain and are thought to be important for neuronal development and function. In pathogens, sialic acids can serve as receptors for viruses, such as influenza viruses, and can be utilized by bacteria to adhere to host cells. The study of sialic acids, known as sialomics, is an active area of research aiming to understand their complex roles in health and disease.