Guanine

Guanine (2-amino-6-oxypurine)one offour main nitrogenous bases foundnucleic acids (e.g., DNARNA). Guanine ispurine derivativein Watson-Crick base pairing forms hydrogen bondscytosine. The nucleosidecalled guanosine.

Guaninealsoname ofwhite amorphous substance found inscalescertain fishes,guanosea-birds, andliverpancreasmammals.