purine

A double-ringed, crystalline organic base, C₅H₄N₄, not known to occur naturally, from which is derived the nitrogen bases adenine and guanine, as well as uric acid as a metabolic end product.

Any of a group of organic compounds structurally related to purine, particularly adenine and guanine, and also caffeine, uric acid, theobromine, and theophylline.

Any of a class of organic heterocyclic base containing fused pyrimidine and imidazole rings; they are components of nucleic acids

any of several bases that are derivatives of purine

a colorless crystalline organic base containing nitrogen; the parent compound of various biologically important substances