Reaction: EXT1:EXT2 transfers GlcNAc to the terminal GlcA residue
- in pathway: HS-GAG biosynthesis
Exostosin1 and 2 (EXT1 and 2) are dual specificity enzymes which catalyze the addition of N acetylglucosamine (GlcNAc) and glucuronate (GlcA) to extend the GAG chain on the protein linker sequence. Heparan is synthesized once GlcNAc is transferred to this sequence. EXT1 and 2 form a heterodimer which translocates to the Golgi apparatus from the ER membrane (McCormick et al. 2000). Defects in EXT1 or 2 cause the hereditary bone disorders multiple exostoses type 1 (MIM:133700) and 2 (MIM:133701) (Wuyts et al. 1998, Bernard et al. 2001).
Reaction - small molecule participants:
UDP [Golgi lumen]
UDP-GlcNAc [Golgi lumen]
Reactome.org reaction link: R-HSA-2022919
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Reaction input - small molecules:
UDP-N-acetyl-alpha-D-glucosamine(2-)
Reaction output - small molecules:
UDP(3-)
Reactome.org link: R-HSA-2022919