Gal-glycan-protein N-glycan-protein B4GALTs add galactose to the N-glycan precursor Authored: Jassal, B, 2011-12-15 EC Number: 2.4.1.38 Edited: Jassal, B, 2011-12-15 Pubmed11588157 Pubmed11901181 Pubmed17021253 Pubmed1714903 Pubmed9597550 Reactome Database ID Release 432025723 Reactome, http://www.reactome.org ReactomeREACT_120962 Reviewed: D'Eustachio, P, 2012-03-28 The family of beta 4-galactosyltransferases (B4GALTs) is composed of at least six known members with different Km and acceptor specifities (Guo et al. 2001) that probably originated by gene duplication (Lo et al. 1998). They mediate the transfer of galactose to N-glycan structures which form the beginning of keratan sulfate biosynthesis. B4GALT1 is associated with Congenital Disorder of Glycosylation of type IId (Hansske et al. 2002), and is expressed as two splicing isoforms of which only one is localizated in the Golgi system (Lopez et al. 1991, Schaub et al. 2006).