Molecular Classification
Enzyme, Glycosyltransferase, Type II membrane protein
Other Names
B4GALT1, Galactosyltransferase I, beta4Gal-T1, Lactose synthase (when in complex with alpha-lactalbumin)
Disease Roles
Congenital disorders of glycosylationCancer (aberrant glycosylation observed in some tumors)Other metabolic diseases (glycan defects may play a role)

Beta-1,4-galactosyltransferase 1 Overview

Beta-1,4-galactosyltransferase 1 (β4Gal-T1) is a type II membrane-bound enzyme located in the trans-Golgi network that catalyzes the transfer of galactose from UDP-galactose to N-acetylglucosamine (GlcNAc) residues on glycoproteins and glycolipids, forming Galβ1-4GlcNAc units. It is encoded by the B4GALT1 gene, one of a family of seven related human genes with specialized functions. This enzyme is central to the biosynthesis of glycoproteins' and glycolipids' carbohydrate portions and is also involved in lactose synthesis in the lactating mammary gland, where it associates with alpha-lactalbumin. β4Gal-T1 has a specialized structural topology that includes a short N-terminal cytoplasmic domain, a single membrane-spanning region, and a large C-terminal catalytic domain that faces the Golgi lumen. Its activity and substrate specificity are modulated by protein conformational changes and interaction with alpha-lactalbumin, enabling dynamic regulation. Mutations in the B4GALT1 gene can lead to congenital glycosylation disorders, and changes in its expression or function are associated with various disease states, including cancer[1][2][3][5][6].

Mechanism of Action

Inhibition or modification of glycosyltransferase activity, potentially altering glycan structures on glycoproteins

Biological Functions

Glycoconjugate biosynthesis
Lactose biosynthesis (in mammary gland)
Protein glycosylation

Disease Associations

Congenital disorders of glycosylation
Cancer (aberrant glycosylation observed in some tumors)
Other metabolic diseases (glycan defects may play a role)

Safety Considerations

  • Essential role in protein processing; inhibition may disrupt normal glycosylation in multiple tissues
  • Genetic deficiency leads to congenital glycosylation disorders

Interacting Drugs

None approved specifically targeting this enzyme as of now; small molecule inhibitors can be experimentally developed

Associated Biomarkers

Biomarker
Abnormal glycosylation patterns assessed in congenital glycosylation disorders
Expression level changes in certain cancers