Sialic acid

Sialic acid is a derivative of 9-carbon monosaccharide. It is a naturally occurring carbohydrate. It was originally isolated from the submandibular gland mucin, hence its name. There are more than 50 kinds of sialic acid found so far, most of which are 2-keto-3-deoxy-D-glycerol-D-galactonanulose (KDN) and 5-acetylamino-3,5-dideoxy- D-glycerol-D-galactosylnonulose (NeuAc) derivative, of which N-acetyl neuraminic acid (NeuAc) accounts for more than 99%, so the commonly referred to as sialic acid, If not specified, it generally refers to NeuAc. As the main type of sialic acid, NeuAc is mainly located at the end of non-reducing oligosaccharides such as glycoproteins or glycolipids in the form of α-glycosides. NeuAc and its derivatives play important roles in many physiological and immune recognition processes, such as cell adhesion, glycoprotein stability, cytotoxicity and tumor metastasis, etc., which have received more and more attention. Derivatives with sialic acid as precursors are increasingly used in antiviral drugs, drugs for the treatment of neurological diseases, and diagnostic reagents.