Molecular Classification
Enzyme, Glycosyltransferase, Type II transmembrane protein
Other Names
Alpha-(1→3)-galactosyltransferase, α₁₋₃GalT, N-acetyllactosaminide alpha-(13)-galactosyltransferase, GGTA, GALT
Disease Roles
Xenotransplantation rejectionAlpha-gal syndrome (red meat allergy)Potential role in pathogen defense

Alpha-1,3-galactosyltransferase Overview

Alpha-1,3-galactosyltransferase (αGT) is a glycosyltransferase enzyme responsible for synthesizing the Galα(1–3)Galβ(1–4)GlcNAc epitope (alpha-Gal). It is absent in humans, apes, and Old World monkeys, leading to the production of anti-alpha-Gal antibodies. Its presence in other mammals poses a significant barrier to xenotransplantation. Furthermore, the alpha-Gal epitope is implicated in IgE-mediated allergic reactions following tick bites. Recombinant forms can be used for *in vitro* glycoprotein modification.

Mechanism of Action

Catalyzes the transfer of a galactose residue from UDP-galactose to terminal N-acetyllactosamine units, forming an α-1,3 linkage.

Biological Functions

Glycosylation
Synthesis of Galα(1–3)Galβ(1–4)GlcNAc epitope
Immune response modulation

Disease Associations

Xenotransplantation rejection
Alpha-gal syndrome (red meat allergy)
Potential role in pathogen defense

Safety Considerations

  • Hyperacute rejection in xenotransplantation
  • IgE-mediated allergic reactions (alpha-gal syndrome)