Purine bases: Structure and Properties

 Purine bases

Structure of purine bases

Purine bases are derived from the parent compound purine. Purine contains the heterocyclic ring system. Fusion of the pyrimidine ring with imidazole yields the purine ring (Fig. 7.2).


The purine bases present in nucleic acids are adenine and guanine. Other purine bases are hypoxanthine and xanthine. They are intermediates in the formation of adenine and guanine nucleotides.

Properties of purine bases

·           Purine bases are sparingly soluble in water.

·           They absorb light in UV region at 260 nm. This property is used for the detection of and the quantification of purine nucleotides.

·           They are capable of forming hydrogen bonds.

·           They exhibit keto-enol tautomerism at body pH.

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