chondroitin(1)-core proteins chondroitin(2)-core proteins A glucuronate moiety is added to chondroitin A glucuronate 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. These three enzymes require divalent metals as cofactors, manganese producing the highest activities. Another candidate enzyme, chondroitin sulfate glucuronyltransferase (CHPF2) possess only beta-1,3-glucuronic acid transferase activity (Izumikawa et al. 2008, Gotoh et al. 2002). Defects in CHSY1 cause Temtamy preaxial brachydactyly syndrome (TPBS) (MIM:605282) (Tian et al. 2010, Li et al. 2010). Authored: Jassal, B, 2011-11-04 EC Number: 2.4.1.226 Edited: Jassal, B, 2011-11-04 Pubmed11514575 Pubmed12145278 Pubmed12761225 Pubmed12907687 Pubmed18316376 Pubmed21129727 Pubmed21129728 Reactome Database ID Release 431971491 Reactome, http://www.reactome.org ReactomeREACT_120993 Reviewed: D'Eustachio, P, 2012-03-28