Galactosylxylosylprotein 3-beta-galactosyltransferase

In enzymology, a galactosylxylosylprotein 3-beta-galactosyltransferase is an enzyme that catalyzes the chemical reaction


 * UDP-galactose + 4-beta-D-galactosyl-O-beta-D-xylosylprotein $$\rightleftharpoons$$ UDP + 3-beta-D-galactosyl-4-beta-D-galactosyl-O-beta-D-xylosylprotein

Thus, the two substrates of this enzyme are UDP-galactose and 4-beta-D-galactosyl-O-beta-D-xylosylprotein, whereas its two products are UDP and 3-beta-D-galactosyl-4-beta-D-galactosyl-O-beta-D-xylosylprotein.

This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-galactose:4-beta-D-galactosyl-O-beta-D-xylosylprotein 3-beta-D-galactosyltransferase. Other names in common use include galactosyltransferase II, and uridine diphosphogalactose-galactosylxylose galactosyltransferase. This enzyme participates in chondroitin sulfate biosynthesis and glycan structures - biosynthesis 1. It employs one cofactor, manganese.