Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA.

The others are adenine, cytosine, thymine, and uracil. With the formula C₅H₅N₅O, guanine is a derivative of purine.

Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA and uracil only in RNA.

• Miyakawa, S., Murasawa, K., Kobayashi, K., Sawaoka, AB. "Abiotic synthesis of guanine with high-temperature plasma." Orig Life Evol Biosph. 30(6): 557-66, Dec. 2000.
• Horton, H.R., Moran, L.A., Ochs, R.S., Rawn, J.D., Scrimgeour, K.G. "Principles of Biochemistry." Prentice Hall (New Jersey). 3rd Edition, 2002.
• Lister, J.H. "Part II Purines." The Chemistry of Heterocyclic Compounds. Wiley-Interscience (New York). 1971.

• Computational Chemistry Wiki Archived 2007-11-01 at the Wayback Machine
• Good Guanine reference

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