Carbohydrate Synthase 3 (CHSY3)

CSS3 is a glycosyltransferase that has both glucuronyltransferase and N-acetylgalactosaminyltransferase activities. The deduced 882-amino acid protein shares 62% sequence homology with CHSY1. It contains a predicted transmembrane domain and 3 predicted N-glycosylation sites. CSS3 also contains 2 DXD motifs, which are conserved in many glycosyltransferases, and several other glycosyltransferase motifs. Quantitative PCR assays showed that CSS3 transcripts are ubiquitously expressed, but at much lower levels than CHSY1.CSS3 acts as a chondroitin sulfate synthase and possesses glucuronyltransferase and N-acetylgalactosaminyltransferase activities on chondroitin, chondroitin synthase polymer, and associated oligosaccharides, although at a much lower specific activity than that observed for CHSY1.