Description: The GlycoEnzDB is a manually curated glycoEnzyme database, primarily focused on humans. It covers 390 enzymes across 28 pathway maps. Facilities are also available to create custom glycosylation reaction pathways using experimental data in SBML format and for pathway simulation
Contacts: Sriram Neelamegham (firstname.lastname@example.org), Yusen Zhou (email@example.com) or Ted Groth (firstname.lastname@example.org).
• The GalNAcT-I activity catalyzes GalNAc transfer toward GlcA in the linkage tetrasaccharide (GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-). This is strongly mediated by CSGalNAcT1 (ChGn1) but can also be performed by CSGalNAcT-II (ChGn2).
• GalNAcT-II catalyzes elongation activity to create repeating disaccharide unit (GlcAβ1-3GalNAcβ1-4)n in the CS chain. This is more readily performed by CSGalNAcT2. Mice lacking CSGalNAcT1 exhibit dwarf phenotype with less cartilage development
• Overall, CSGalNAcT1 and CSGalNAcT2 mediate both initiation and elongation of CS via GalNAcT activity
• CHSY1 (Chondroitin synthase-1/chondroitin sulfate synthase-1 (CSS1)) and CHSY3 (chondroitin synthase-3/chondroitin sulfate synthase-3 (CSS3)) exhibit dual glycosyltransferase activities of β1,3 GlcA-T and β1,4 GalNAc-T for CS initiation and elongation
• CHPF (chondroitin sulfate synthase-2 (CSS2)) also exhibits dual glycosyltransferase activities of β1,3 GlcA-T and β1,4 GalNAc-T for CS initiation and elongation. Its activity is similar to that of CSS1 and CSS3.
• CHPF2 (chondroitin polymerizing factor 2/chondroitin sulfate glucuronyltransferase (CSGlcA-T)) transfers glucuronic acid (GlcUA) from UDP-GlcUA to N-acetylgalactosamine in the elongating chondroitin polymer. It does not have GalNAcT activity.
• CS is also present broadly in the tissues and abundantly in the cartilage and brain. Aggrecan contains abundant CS in cartilage.