Reaction: Defective HGSNAT does not acetylate Heparan sulfate chain(3)
- in pathway: MPS IIIC - Sanfilippo syndrome C
Enzyme misfolding due to missense mutations results in incorrect glycosylation therefore HGSNAT is not targeted to the lysosome and stays in the ER (Feldhammer et al. 2009). This, together with mutations giving rise to nonsense-mediated mRNA decay (Fedele & Hopwood 2010), appear to be the major molecular mechanisms underlying MPSIIIC. More than 50 mutations are known in the HGSNAT gene. Some of them drastically reduce enzyme activity; W403C/A615T double mutant (Fedele & Hopwood 2010), R344C, S518F and R384X (Fedele et al. 2007, Ruijter et al.2008).
Reaction - small molecule participants:
Heparan sulfate chain(3) [lysosomal lumen]
Ac-CoA [cytosol]
Reactome.org reaction link: R-HSA-9036056
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Reaction input - small molecules:
alpha-D-GlcN-(1->4)-beta-D-IdoA2S-(1->4)-alpha-D-GlcNS3S-(1->4)-beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl-yl group
acetyl-CoA(4-)
Reaction output - small molecules:
Reactome.org link: R-HSA-9036056