NDST4

NDST4 encodes heparan sulfate/heparin GlcNAc N-deacetylase/N-sulfotransferase 4. This enzyme has dual enzymatic activities: N-deacetylase activity and N-sulfotransferase activity. There are four isoenzymes of NDST in humans. NDST deacetylates the N-acetyl group of GlcNAc and transfers the sulfate group using PAPS as the sulfate donor. This reaction is the first step in the sulfation of heparan sulfate, followed by epimerization of GlcA and sulfation of the C2 position of GlcA and the C6- and C3-positions of GlcNAc. The NDST1 and NDST2 genes show ubiquitous expression patterns, while NDST3 and NDST4 genes show tissue-specific expression patterns. NDST3 and NDST4 show tissue-specific gene expression.