has role purines mancude organic heterobicyclic parent purine A heterobicyclic aromatic organic compound comprising a pyrimidine ring fused to an imidazole ring; the parent compound of the purines. C5H4N4 CHEBI:35584 HMDB:HMDB01366 KEGG:C15587 MetaCyc:PURINE PMID:12865945 PMID:24088627 chebi_ontology purine fundamental metabolite