alpha23sialyltransferases

Alpha2,3-sialyltransferases are a family of enzymes that play a crucial role in the biosynthesis of complex carbohydrates, specifically in the formation of alpha2,3-linked sialic acid residues. These enzymes are responsible for catalyzing the transfer of sialic acid, a nine-carbon sugar acid, from a donor molecule, typically cytidine-5'-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac), to an acceptor molecule, usually a terminal galactose or N-acetylgalactosamine residue. The resulting alpha2,3-sialyl linkage is a common structural motif found in various glycoconjugates, including glycoproteins and glycolipids, throughout the animal kingdom.

The biological significance of alpha2,3-sialyltransferases stems from the diverse functions associated with the alpha2,3-sialyl motifs they create. These motifs are involved in a wide range of cellular processes, such as cell-cell recognition, immune responses, and the modulation of protein activity. For instance, alpha2,3-sialylated glycans are important for the adhesion of leukocytes to endothelial cells during inflammation and are recognized by specific lectins. Furthermore, alterations in the expression or activity of alpha2,3-sialyltransferases have been implicated in various disease states, including cancer and infectious diseases, making them targets for therapeutic intervention. The human genome encodes several distinct alpha2,3-sialyltransferases, each exhibiting specific substrate preferences and expression patterns, contributing to the complexity and specificity of cellular glycosylation.