Bifunctional heparan sulfate N-deacetylase/N-sulfotransferase 3 is an enzyme that in humans is encoded by the NDST3 gene. It catalyses the reaction:<blockquote>3'-phosphoadenylyl sulfate + ñ-<small>D</small>-glucosaminyl-[<nowiki/>heparan sulfate]<sub>(n)</sub> = adenosine 3',5'-bisphosphate + 2 H<sup>+</sup> + N-sulfo-ñ-<small>D</small>-glucosaminyl-[heparan sulfate]<sub>(n)</sub></blockquote>This is a step in the production of heparin.
Mutations in NDST3 have been linked to schizophrenia.