N-acetylneuraminic acid, often abbreviated as Neu5Ac, is a type of sialic acid, a family of nine-carbon sugars. It is commonly found on the surface of cells in animals and plays a crucial role in various biological processes, including cell recognition and signaling. Neu5Ac is important for immune response and is involved in the development of the nervous system. This compound is synthesized from UDP-N-acetylglucosamine and is a key component of glycoproteins and glycolipids. N-acetylneuraminic acid can influence the binding of pathogens, such as viruses and bacteria, to host cells, making it significant in the study of infections and diseases.