Guanine
[CAS# 73-40-5]

Identification

• Classification: Biochemical >> Plant extracts
• Name: Guanine
• Synonyms: 2-Amino-1,7-dihydro-6H-purin-6-one; 2-Aminohypoxanthine; 2-Amino-6-hydroxypurine
• Molecular Formula: C₅H₅N₅O
• Molecular Weight: 151.13
• CAS Registry Number: 73-40-5
• EC Number: 200-799-8
• SMILES: C1=NC2=C(N1)C(=O)NC(=N2)N

Properties

• Density: 2.2±0.1 g/cm³ Calc.^*, 2.2 g/mL (Expl.)
• Melting point: 300 °C (Expl.)
• Solubility: practically insoluble in water (Expl.)
• Index of refraction: 2.047 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - single exposure	STOT SE	3	H371

Discovery and Applications

Guanine is one of the four primary nucleobases found in the nucleic acids DNA and RNA, essential molecules for the storage and transmission of genetic information in living organisms. It is classified as a purine base, characterized by a fused double-ring structure composed of a six-membered and a five-membered nitrogen-containing ring.

The discovery of guanine dates back to the mid-19th century when it was first isolated from guano, the accumulated excrement of seabirds and bats, which was rich in nitrogenous compounds. The name guanine is derived from this source. Since then, guanine has been identified as a fundamental building block of nucleic acids, playing a crucial role in genetics and cellular function.

In the structure of DNA and RNA, guanine pairs specifically with cytosine through three hydrogen bonds, contributing to the stability of the double helix and the fidelity of genetic information. This complementary base pairing is central to DNA replication and transcription processes, ensuring accurate copying and expression of genetic material.

Guanine’s chemical properties include a planar structure and the ability to participate in hydrogen bonding, which facilitates the formation of stable base pairs and higher-order nucleic acid structures. Additionally, guanine exhibits fluorescence and electrochemical properties that have been utilized in biochemical assays and molecular diagnostics.

Beyond its role in nucleic acids, guanine is involved in various biological processes. It serves as a precursor for important biomolecules such as guanosine triphosphate (GTP), which is critical in energy transfer, signal transduction, and protein synthesis. Guanine derivatives are also part of cofactors and second messengers that regulate cellular activities.

The synthesis of guanine occurs through complex metabolic pathways involving purine biosynthesis, primarily in the liver. Cells can also salvage guanine from nucleic acid turnover, conserving resources and maintaining nucleotide pools.

In laboratory research and biotechnology, guanine and its analogs are used to study nucleic acid structure, function, and interactions. Guanine-rich sequences have been found to form unique secondary structures known as G-quadruplexes, which have implications in gene regulation and are potential targets for therapeutic intervention.

In summary, guanine is a fundamental purine nucleobase integral to the structure and function of DNA and RNA. Its discovery from natural sources led to profound insights into genetic coding and molecular biology. Guanine’s ability to pair specifically with cytosine underpins the stability and transmission of genetic information, and its biological roles extend beyond nucleic acids to essential cellular processes involving energy and signaling.

References

1979. Isocratic separation of DNA bases and deoxyribonucleosides by high-performance liquid chromatography on anex OSTION. Analytical Biochemistry, 94(2).
DOI: 10.1016/0003-2697(79)90353-1

1991. An endonuclease activity of Escherichia coli that specifically removes 8-hydroxyguanine residues from DNA. Mutation Research/DNA Repair, 250(1-2).
DOI: 10.1016/0921-8777(91)90035-n

2024. Tissue Inhibitor of Metalloproteinase 2 (TIMP 2) Promotor 418 G > C Polymorphism in Non-alcoholic Fatty Liver Disease (NAFLD) Patients of Eastern States of India. Indian Journal of Clinical Biochemistry.
DOI: 10.1007/s12291-024-01287-9