In enzymology, a glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase (EC 220.127.116.11) is an enzyme that catalyzes the chemical reaction
- UDP-galactose + glycoprotein N-acetyl-D-galactosamine UDP + glycoprotein D-galactosyl-1,3-N-acetyl-D-galactosamine
Thus, the two substrates of this enzyme are UDP-galactose and glycoprotein N-acetyl-D-galactosamine, whereas its two products are UDP and glycoprotein D-galactosyl-1,3-N-acetyl-D-galactosamine.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-galactose:glycoprotein-N-acetyl-D-galactosamine 3-beta-D-galactosyltransferase. This enzyme is also called uridine diphosphogalactose-mucin beta-(1->3)-galactosyltransferase. This enzyme participates in o-glycan biosynthesis and glycan structures - biosynthesis 1.