Reactome: A Curated Pathway Database

HGSNAT acetylates the terminal N-glucosamine in heparan sulfate

Stable Identifier
R-HSA-1678660
Type
Reaction
Species
Homo sapiens
Compartment
Locations in the PathwayBrowser
Summation

Heparan-alpha-glucosaminide N-acetyltransferase (HGSNAT) acetylates the non-reducing terminal alpha-glucosamine residue of heparan sulfate. This is a critical reaction for the degradation of heparan sulfate because there is no enzyme that can act on the unacetylated glucosamine molecule. The mechanism by which HGSNAT uses cytosolic acetyl-CoA to transfer the acetyl group to the lysosomal luminal substrate is unknown (Fan et al. 2006). A catalytically inactive 77kDa precursor is transported to the lysosome and is cleaved into a 29kDa N-terminal alpha-chain and a 48kDa C-terminal beta-chain, which are assembled into active 440kDa oligomers in the lysosomal membrane (Durand et al. 2010). Defects in HGSNAT cause mucopolysaccharidosis type IIIC (MPSIIIC, MIM:252930), also called Sanfilippo C syndrome (Fan et al. 2006, Hrebicek et al. 2006).

Literature References
Participants
Participant Of
This entity is regulated by:
Title Physical Entity Activity
heparan-alpha-glucosaminide N-acetyltransferase activity of HGSNAT oligomer [lysosomal membrane] HGSNAT oligomer [lysosomal membrane] heparan-alpha-glucosaminide N-acetyltransferase activity (0015019)
Orthologous Events