One such medium that is commonly used is HAT medium, which contains hypoxanthine, aminopterinand thymidine.
12.
A derivative of hypoxanthine was subsequently shown by others to be the key product of purine biosynthesis.
13.
In prolonged ischemia ( 60 minutes or more ), hypoxanthine is formed as breakdown product of radicals.
14.
Some examples include hypoxanthine, dihydrouracil, methylated forms of uracil, cytosine, and guanine, as well as modified nucleoside pseudouridine.
15.
Hypoxanthine is then oxidatively catabolized first to xanthine and then to uric acid, and the reaction is catalyzed by the enzyme xanthine oxidase:
16.
Decreased levels of hypoxanthine guanine phosphoribosyl transferase ( HGPRT ) causes this accumulation, as PRPP is a substrate used by HGPRT during purine salvage.
17.
The Cobra virus also knocks out the gene for the enzyme hypoxanthine-guanine phosphoribosyltransferase ( HGPRT ), whose absence causes Lesch-Nyhan syndrome.
18.
Allopurinol, which weakly inhibits xanthine oxidase, is an analog of hypoxanthine that is hydroxylated by xanthine oxidoreductase at the 2-position to give oxipurinol.
19.
Ethanol also increases the plasma concentrations of hypoxanthine and xanthine via the acceleration of adenine nucleotide degradation, and is a possible weak inhibitor of xanthine dehydrogenase.
20.
Specifically, hAAG is able to efficiently identify and excise 3-methyladenine, 7-methyladenine, 7-methylguanine, 1N-ethenoadenine and hypoxanthine.
