Purine

Purine is a heterocyclic aromatic organic compound that consists of a pyrimidine ring fused to an imidazole ring. Purines, including substituted purines and their tautomers, are the most widely occurring nitrogen-containing heterocycles in nature. Purines and pyrimidines make up the two groups of nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides and two of the four ribonucleotides, the respective building-blocks of DNA and RNA, are purines.

Structure and properties

Purines are aromatic compounds that are composed of two rings, a six-membered ring with two nitrogen atoms and a five-membered ring with two nitrogen atoms. The purine structure is considered a bicyclic structure, with the two rings sharing two atoms. The larger, six-membered ring is a pyrimidine ring, and the smaller, five-membered ring is an imidazole ring.

Biosynthesis

Purines are biologically synthesized as nucleotides (bases attached to ribose). Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is the first compound in the pathway to have a completely formed purine ring system.

Function

Purines play crucial roles in a number of biological processes. They are components of DNA and RNA, energy molecules such as ATP and GTP, coenzymes such as NADH, and signaling molecules such as cAMP and cGMP.

Disease relevance

Abnormalities in purine metabolism can lead to, or increase susceptibility to, a variety of diseases. These include gout, Lesch-Nyhan syndrome, ADA deficiency, and others.

See also

• Pyrimidine
• Nucleotide
• DNA
• RNA
• Gout
• Lesch-Nyhan syndrome
• ADA deficiency

Purine Resources
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