A purine is a heterocyclic aromatic organic compound that consists of a pyrimidine ring fused to an imidazole ring. Purine gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers, are the most widely occurring nitrogen-containing heterocycle in nature. Purine is water soluble. Purines are found in high concentration in meat and meat products, especially internal organs such as liver and kidney.