Adenine (C₅H₅N₅) — Properties, Uses & Safety

Overview

Adenine (C5H5N5) is one of the four nucleobases found in DNA and one of the four in RNA, making it fundamental to the storage and transmission of genetic information in all living organisms. With a molar mass of 135.13 g/mol, adenine is a purine base — its structure consists of two fused nitrogen-containing rings (a pyrimidine ring fused to an imidazole ring), giving it a flat, planar geometry ideal for stacking within the DNA double helix. Adenine was first isolated from pancreatic tissue in 1885 by Albrecht Kossel, who later won the Nobel Prize for his work on nucleic acids. In DNA, adenine pairs specifically with thymine (T) through two hydrogen bonds (A=T), while in RNA it pairs with uracil (U), also through two hydrogen bonds (A=U). This complementary base pairing — adenine with thymine/uracil, and guanine with cytosine — is the foundation of the genetic code and enables DNA replication, transcription, and translation. The specificity of base pairing arises from the precise arrangement of hydrogen bond donors and acceptors on each base, a beautiful example of molecular recognition driven by intermolecular forces. Beyond its role in nucleic acids, adenine is a component of several critically important biomolecules. It is part of adenosine triphosphate (ATP), the universal energy currency of cells; nicotinamide adenine dinucleotide (NAD⁺/NADH) and flavin adenine dinucleotide (FAD/FADH2), essential coenzymes in metabolic redox reactions; S-adenosylmethionine (SAM), the primary methyl group donor in biological methylation reactions; and cyclic AMP (cAMP), a crucial second messenger in cell signaling. Adenine is biosynthesized through the de novo purine synthesis pathway, a complex series of enzymatic reactions that builds the purine ring system step by step from simple precursors including glycine, glutamine, and formate. GHS classifications include irritant and health hazard warnings for the pure compound. For chemistry students, adenine is essential for understanding heterocyclic aromatic chemistry, hydrogen bonding and molecular recognition, the structure of nucleic acids, the central dogma of molecular biology, and the remarkable versatility of a single molecular scaffold in biochemistry. Studying adenine reveals how the principles of organic chemistry underpin the most fundamental processes of life.

IUPAC Name

7H-purin-6-amine

CAS Number

73-24-5

PubChem CID

190

Molecular Formula

C₅H₅N₅

Molar Mass

135.127 g/mol

State at STP

solid

Appearance

White to off-white crystalline powder