Hypoxanthine is a naturally occurring purine derivative, and one of the products of the action of xanthine oxidase on xanthine, though more normally in purine degradation, hypoxanthine is oxidized by xanthine oxidase to form xanthine. It is very occasionally found as a constituent of nucleic acids.
Hypoxanthine is a base found in an intermediate of purine nucleotide biosynthesis. Figure 22.4 summarizes the pathway leading from phosphoribosyl-1-pyrophosphate (PRPP) to the first fully formed purine nucleotide, inosine 5'-monophosphate (IMP), also called inosinic acid. IMP contains as its base, hypoxanthine. In addition, hypoxanthine can be converted back to IMP in purine nucleotide salvage biosynthesis (by the enzyme HGPRT).
Complete deficiency of HGPRT results in gout-related arthritis, dramatic malfunction of the nervous system, behavioral disorders, learning disability, and hostile or aggressive behavior, often self directed. In the most extreme cases, patients nibble at their fingertips or, if restrained, their lips, causing severe self-mutilation.
Allopurinol, which is similar to hypoxanthine (see here), is used to treat gout because it inhibits xanthine oxidase, leading to accumulation of hypoxanthine and xanthine, both of which are more soluble and more readily excreted than uric acid, the chemical that causes gout.
CAS NO.: 68-94-0
Molecular weigt: C5H4N4O
Synonyms: Hypoxanthine; 1,7-Dihydro-6H-purin-6-one; Purine-6-ol; 6-Hydroxypurine; 6-Oxypurine