bifunctional heparan sulfate N-deacetylase/N-sulfotransferase 4; glucosaminyl N-deacetylase/N-sulfotransferase 4; NDST-4; N-heparan sulfate sulfotransferase 4; N-HSST 4; includes: heparan sulfate N-deacetylase 4; heparan sulfate N-sulfotransferase 4 (NDST4, HSST4)

Function

• bifunctional enzyme in heparin/heparan sulfate synthesis
• catalyzes both N-deacetylation & N-sulfation of glucosamine of glycosaminoglycan in heparan sulfate.
• modifies GlcNAc-GlcA dissacharide repeating sugar backbone to make N-sulfated heparosan, substrate for later modifications in heparin biosynthesis
• high deacetylase activity but low sulfotransferase activity

3'-phosphoadenylyl sulfate + [heparan sulfate]-glucosamine
              <-->
     adenosine 3',5'-bisphosphate +
    [heparan sulfate]-N-sulfoglucosamin

Structure

• monomer
• belongs to the sulfotransferase 1 family, NDST subfamily

Compartment

Golgi apparatus

Comparative biology

• presence of 4 different heparan sulfate N-deacetylase/ N-sulfotransferase enzymes in mammals, & differences in enzyme activity suggest that some initiate heparan sulfate modification/sulfation reactions, whereas others extend already modified heparan sulfate sequences

More general terms

• sulfotransferase
• hydrolase
• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=64579
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:64579
• UniProt: http://www.uniprot.org/uniprot/Q9H3R1.html