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Enzyme
Compound
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Target Concepts:
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Query: UNIPROT:P00492 (
hypoxanthine-guanine phosphoribosyltransferase
)
2,385
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Inhibition of IMP dehydrogenase (EC 1.2.1.14) by ribavirin causes the normal human lymphoblast to excrete increased amounts of newly formed purine into the culture medium. In order for ribavirin to be active as an inhibitor of the dehydrogenase, this synthetic nucleoside must be phosphorylated. The effect of ribavirin on purine excretion has been determined with a normal lymphoblast line, and with lymphoblast lines deficient in
hypoxanthine phosphoribosyltransferase
(IMP:pyrophosphate phosphoribosyl-transferase, EC 2.4.2.8), in adenosine kinase (ATP:adenosine 5'-phosphotransferase, EC 2.7.1.20), and in both
hypoxanthine phosphoribosyltransferase
and adenosine kinase. Resistance to the effect of ribavirin on purine excretion was associated only with those cell lines deficient in adenosine kinase activity. These cell lines have normal
deoxyadenosine kinase
(
ATP:deoxyadenosine 5'-phosphotransferase
,
EC 2.7.1.76
) activity. Therefore, the nucleoside kinase activity responsible for ribavirin phosphorylation is adenosine kinase.
...
PMID:Adenosine kinase initiates the major route of ribavirin activation in a cultured human cell line. 21 Apr 48
Mutant sublines were derived of S49 mouse T-lymphoma cells that were resistant to tritiated deoxyadenosine. Twenty-five isolates that were selected in 1 microCi/ml of the nucleoside were cross-resistant to 6-thioguanine, were sensitive to HAT (hypoxanthine, aminopterin, and thymidine), and contained less than 1% of
hypoxanthine phosphoribosyltransferase
activity in wild-type cells. One of the mutant clones, S49-dA2, was further subjected to selection in a medium containing 2 microCi/ml tritiated deoxyadenosine and 1 microgram/ml deoxycoformycin, an inhibitor of adenosine deaminase. All resistant subclones were cross-resistant to tubercidin, 6-methylmercaptopurine riboside, and arabinosyladenine. One of the subclones, S49-12, was completely devoid of adenosine kinase and was partially deficient in
deoxyadenosine kinase
. This subclone, however, contained wild-type levels of deoxycytidine kinase. DEAE chromatography of the wild-type cell extracts revealed two deoxyadenosine phosphorylating activities, one of which coeluted with adenosine kinase and was the enzyme missing in S49-12. The other species phosphorylated both deoxyadenosine and deoxycytidine, of which deoxycytidine was the preferred substrate.
...
PMID:Adenosine kinase deficiency in tritiated deoxyadenosine-resistant mouse S49 lymphoma cell lines. 283 56