Keratan(3)-PG Keratan(2)-PG B4GALTs can add galactose to a branch of keratan Authored: Jassal, B, 2011-12-01 EC Number: 2.4.1.38 Edited: Jassal, B, 2011-12-01 Pubmed11588157 Pubmed11901181 Pubmed17021253 Pubmed1714903 Pubmed9597550 Reactome Database ID Release 432046298 Reactome, http://www.reactome.org ReactomeREACT_120770 Reviewed: D'Eustachio, P, 2012-03-28 The family of beta 4-galactosyltransferases (B4GALTs) is composed by 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, in this case, to elongate a branched chain of keratan. 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).