adenines

Adenines, or adenine, is one of the purine nucleobases. With the chemical formula C5H5N5, adenine is 6-aminopurine, a bicyclic aromatic base composed of a fused pyrimidine and imidazole ring. In nucleic acids, adenine pairs with thymine in DNA and with uracil in RNA, contributing to genetic information storage and the three-dimensional structure of the nucleic acids.

Adenine is a fundamental component of several biologically important nucleotides. It forms ATP, ADP, and AMP, the energy-currency nucleotides that power many cellular processes. Adenine is also part of essential cofactors such as NAD+, NADP+, and FAD. When attached to ribose, adenine forms the nucleoside adenosine, which can act as a signaling molecule by binding adenosine receptors in various tissues.

Biosynthesis and metabolism of adenine involve both de novo purine synthesis and salvage pathways. The de novo pathway constructs the purine ring from simple precursors, while salvage enzymes recover adenine and other bases for reuse, notably through adenine phosphoribosyltransferase. In humans, purines are ultimately degraded to uric acid, which is excreted; excess purine breakdown can contribute to hyperuricemia and gout in susceptible individuals.

Adenine is ubiquitous in all life, serving as a fundamental component of DNA, RNA, energy carriers, and essential metabolic cofactors. Its versatile roles underpin both genetic information flow and cellular energetics.