chondroitin(2)-core proteins chondroitin(3)-core proteins GalNAc is added to chondroitin An N-acetylgalactosamine (GalNAc) moiety is added to the chondroitin chain by dual-activity enzymes, the chondroitin sulfate synthases 1-3 (CHSY1, CHPF and CHSY3 respectively) (Kitagawa et al. 2001, Yada et al. 2003, Yada et al. 2003b). They possess both beta-1,3-glucuronic acid and beta-1,4-N-acetylgalactosamine transferase activity, the latter activity used in this reaction. These three enzymes require divalent metals as cofactors, manganese producing the highest activities. The repeated disaccharide units of GlcA-GalNAc identify this glycosaminoglycan as chondroitin. Authored: Jassal, B, 2011-11-04 EC Number: 2.7.1.61 Edited: Jassal, B, 2011-11-04 Pubmed11514575 Pubmed12761225 Pubmed12907687 Reactome Database ID Release 431971487 Reactome, http://www.reactome.org ReactomeREACT_121192 Reviewed: D'Eustachio, P, 2012-03-28