5-amino-1-(5-phosphonato-beta-D-ribosyl)imidazol-3-ium chebi_ontology PMID:3530323 PMID:2684279 MetaCyc:5-PHOSPHORIBOSYL-5-AMINOIMIDAZOLE 5-amino-1-(5-phospho-beta-D-ribosyl)imidazole CHEBI:137981 An organophosphate oxoanion obtained by deprotonation of the phosphate OH groups as well as protonation of the endocyclic nitrogen at position 3 in the imidazole ring of 5-amino-1-(5-phospho-beta-D-ribosyl)imidazole. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). 5-amino-1-(5-phospho-beta-D-ribosyl)imidazole organophosphate oxoanion