is conjugate acid of histidinium(1+) histidinium(2+) 157.17056 4-(2-ammonio-2-carboxyethyl)-1H-imidazol-3-ium An alpha-amino-acid cation that has formula C6H11N3O2. C6H11N3O2 CHEBI:32532 Gmelin:1151904 HNDVDQJCIGZPNO-UHFFFAOYSA-P InChI=1S/C6H9N3O2/c7-5(6(10)11)1-4-2-8-3-9-4/h2-3,5H,1,7H2,(H,8,9)(H,10,11)/p+2 [NH3+]C(Cc1c[nH]c[nH+]1)C(O)=O chebi_ontology histidine dication histidinediium histidinium(2+) alpha-amino-acid cation