purin Definition

A purin (or purine) is a nitrogen-containing heterocyclic organic compound. It is a tautomeric form of a derivative of imidazole fused to pyrimidine. It is a component of nucleic acids, and its derivatives, such as adenine and guanine, are essential for living organisms. Purines participate in numerous biological processes and are involved in the metabolism of nucleotides, the regulation of gene expression, and the production of ATP (adenosine triphosphate).