HS3ST5 is the rate limiting enzyme for synthesis of HSact. It performs the crucial step modification in the biosynthesis of anticoagulant heparan sulfate (HSact) that is to complete the structure of the antithrombin pentasaccharide binding site. HS3ST5 also generates GlcUA-GlcNS or IdoUA-GlcNS and IdoUA2S-GlcNH2. The substrate-specific O-sulfation generates an enzyme-modified heparan sulfate which acts as a binding receptor to Herpes simplex virus-1 (HSV-1) and permits its entry.HS3ST5 belongs to a group of heparan sulfate 3-O-sulfotransferases (EC 2.8.2.23) that transfer sulfate from 3-prime-phosphoadenosine 5-prime phosphosulfate (PAPS) to heparan sulfate and heparin (Mochizuki et al., 2003 [PubMed 12740361]). [supplied by OMIM]. Sequence Note: The RefSeq transcript and protein were derived from genomic sequence to make the sequence consistent with the reference genome assembly. The genomic coordinates used for the transcript record were based on alignments. PRIMARYREFSEQ_SPAN PRIMARY_IDENTIFIER PRIMARY_SPAN COMP 1-139 AL355498.10 32491-32629 c 140-2744 AL355498.10 25338-27942 c