MeSH note : Involved in the biosynthesis of the linkage region of glycosaminoglycan chains as
part of proteoglycan biosynthesis (chondroitin, dermatan and heparan sulfates); catalyzes
the reaction of UDPgalactose & 4-beta-D-(galactosyl-O-beta-D-xylosylprotein to yield
UDP & 3-beta-D-galactosyl-O-beta-D-xylosylprotein;