is conjugate acid of is tautomer of organosulfonic acid 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid 238.099 238.30560 4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID 4-(2-Hydroxyethyl)-1-piperazineethane sulfonic acid A HEPES that is ethanesulfonic acid in which one of the methyl hydrogens is replaced by a 4-(2-hydroxyethyl)piperazin-1-yl group. A Good's buffer substance, pKa = 7.55 at 20 degreeC. Beilstein:883043 C8H18N2O4S CAS:7365-45-9 CHEBI:32949 CHEBI:42332 CHEBI:42334 Hepes InChI=1S/C8H18N2O4S/c11-7-5-9-1-3-10(4-2-9)6-8-15(12,13)14/h11H,1-8H2,(H,12,13,14) JKMHFZQWWAIEOD-UHFFFAOYSA-N OCCN1CCN(CC1)CCS(O)(=O)=O PDBeChem:EPE PMID:22732654 Reaxys:883043 chebi_ontology 2-[4-(2-hydroxyethyl)piperazin-4-ium-1-yl]ethanesulfonate HEPES 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonate