Isoguanine is a natural isomer of guanine originally isolated from Croton seed but is also a product of oxidative damage to the adenine base in DNA.1,2 It can be formed through oxidative damage to deoxyadenosine and deoxyadenosine-ATP (d-ATP) as well as single- and double-stranded DNA and induces a parallel-stranded DNA structure when incorporated into DNA.2,3 It is mutagenic to S. tymphimurium in the Ames test and induces sister chromatid exchange, a measure of mutagenicity, in isolated human peripheral blood lymphocytes.4
1.Cherbuliez, E., and Bernhard, K.Croton seed. I. Crotonoside (2-hydroxy-6-aminopurine-d-riboside)Helv. Chim. Acta15464-471(1932) 2.Cheng, Q., Gu, J., Compaan, K.R., et al.Isoguanine formation from adenineChemistry18(16)4877-4886(2012) 3.Kamiya, H., and Kasai, H.2-Hydroxyadenine (isoguanine) as oxidative DNA damage: Its formation and mutation inducibilityNucleic Acids Symp. Ser.(34)233-234(1995) 4.Arashidani, K., Iwamoto-Tanaka, N., Muraoka, M., et al.Genotoxicity of ribo- and deoxyribonucleosides of 8-hydroxyguanine, 5-hydroxycytosine, and 2-hydroxyadenine: Induction of SCE in human lymphocytes and mutagenicity in Salmonella typhimurium TA 100Mutat. Res.403(1-2)223-227(1998)