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).
• Heparan sulfates [HS; sulfated GlcNAc(α1-4)GlcA/IdoA(β1-4)] and chondroitin/dermatan sulfates [CS; sulfated GalNAc(β1-4)GlcA/IdoA(β1-3)] are produced on a common GAG core: GlcA(β1-3)Gal(β1-3)Gal(β1-4)Xylβ-O-Ser.
• This core is synthesized by XYLT1/2, B4GalT-7 ('Gal transferase-I'), B3GalT6 ('Gal transferase-II') and B3GAT3 ('GlcA transferase-I').
• Thus, XYLT1/2 initiate the formation of heparan sulfates, chondroitin sulfates and dermatan sulfates.
• XYLTs are typical Type II enzymes with catalytic activity in the Golgi lumen. It is mostly expressed in Cis-Golgi but some activity may be present in late ER.
• Consensus sequence for XYLT1/2 include Serine with include Ser-Gly and a cluster of nearby acidic residues (e.g. Q-E-E-E-G-S-G-G-G-Q-K).
• XYLT2 is ubiquitously expressed. XYLT1 is rarely expressed alone with the possible exception of cartilage derived cells. Many tissue like kidney, brain, spleen, skeletal muscle etc. express both enzymes.
• XylT2 mice are viable, but develop biliary cysts and renal tubule dilation with accompanied liver and renal fibrosis at 4-5 months.