Purines [Chemical/Ingredient] C0034140 M0018169 C26494 Purines N0000008065 D011687 Purines A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism. 8952 Heterocyclic Compounds, 2-Ring [Chemical/Ingredient]