Catalysis of the reaction: 3'-phosphoadenylyl sulfate + alpha-D-glucosaminyl-(heparan sulfate)(n) = 3-sulfo-alpha-D-glucosaminyl-(heparan sulfate)(n) + adenosine 3',5'-bisphosphate + H+. Modifies selected glucosamine residues preceded by GlcA2S.
3-OST-2