Hypoxanthine

Hypoxanthine is a naturally occurring purine derivative.

It is occasionally found as a constituent of nucleic acids where it is present in the anticodon of tRNA in the form of its nucleoside inosine.

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It is one of the products of the action of xanthine oxidase on xanthine, though more normally in purine degradation, hypoxanthine is formed from oxidation of xanthine by xanthine oxidase.

Hypoxanthine-guanine phosphoribosyltransferase converts hypoxanthine into IMP in nucleotide salvage.

Hypoxanthine is also a spontaneous deamination product of adenine. Because of its resemblance to guanine, the spontaneous deamination of adenine can lead to an error in DNA transcription/replication.