purine /pūrˈin or pūrˈēn/ or purin /pūˈrin/

1. A cyclic double-ring crystalline substance C₅H₄N₄, which with oxygen forms uric acid (C₅H₄N₄O₃), and with many derivatives
2. Any of a number of these derivatives, cyclic diureides, such as adenine and guanine, esp one which is part of the nucleotide chains of DNA and RNA

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