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, Mar 2008].