B3GALT

B3GALT, short for beta-1,3-galactosyltransferase, refers to a family of enzymes that catalyze the transfer of galactose from UDP-galactose to acceptor substrates, forming beta-1,3-glycosidic linkages. In humans, the B3GALT family comprises several paralogs, including B3GALT1, B3GALT2, B3GALT3, B3GALT4, B3GALT5, and B3GALT6. These enzymes are typically type II transmembrane proteins located in the Golgi apparatus and belong to the glycosyltransferase class 31. They participate in the biosynthesis of glycoconjugates, contributing to the elongation and modification of glycoprotein and glycolipid lac1ose-containing glycans.

The activity of B3GALT enzymes affects a wide range of glycoconjugates, influencing cell surface properties, signaling, and protein stability. Their substrates are often lactosyl or N-acetyllactosamine-containing acceptors, leading to the formation of beta-1,3-linked structures that participate in glycosphingolipid and glycoprotein pathways. Expression patterns of the paralogs vary, with some showing broad tissue distribution and others exhibiting more restricted expression.

Clinical relevance varies by paralog. Mutations in B3GALT6 have been linked to spondylodysplastic Ehlers-Danlos syndrome, a connective tissue disorder characterized by skeletal abnormalities and joint laxity. Other B3GALT genes are subjects of ongoing research to determine their roles in development, immune function, cancer, and inherited glycosylation disorders.

Overall, B3GALT enzymes serve as key components of the cellular glycosylation machinery, shaping the structure and function of glycoconjugates that influence numerous biological processes.