Linked Life Data

2430286

Source:http://linkedlifedata.com/resource/pubmed/id/2430286

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1986-12-5
pubmed:abstractText
The thymidine analog 3'-azido-3'-deoxythymidine (BW A509U, azidothymidine) can inhibit human immunodeficiency virus (HIV) replication effectively in the 50-500 nM range [Mitsuya, H., Weinhold, K. J., Furman, P. A., St. Clair, M. H., Nusinoff-Lehrman, S., Gallo, R. C., Bolognesi, D., Barry, D. W. & Broder, S. (1985) Proc. Natl. Acad. Sci. USA 82, 7096-7100]. In contrast, inhibition of the growth of uninfected human fibroblasts and lymphocytes has been observed only at concentrations above 1 mM. The nature of this selectivity was investigated. Azidothymidine anabolism to the 5'-mono-, di-, and -triphosphate derivatives was similar in uninfected and HIV-infected cells. The level of azidothymidine monophosphate was high, whereas the levels of the di- and triphosphate were low (less than or equal to 5 microM and less than or equal to 2 microM, respectively). Cytosolic thymidine kinase (EC 2.7.1.21) was responsible for phosphorylation of azidothymidine to its monophosphate. Purified thymidine kinase catalyzed the phosphorylations of thymidine and azidothymidine with apparent Km values of 2.9 microM and 3.0 microM. The maximal rate of phosphorylation with azidothymidine was equal to 60% of the rate with thymidine. Phosphorylation of azidothymidine monophosphate to the diphosphate also appeared to be catalyzed by a host-cell enzyme, thymidylate kinase (EC 2.7.4.9). The apparent Km value for azidothymidine monophosphate was 2-fold greater than the value for dTMP (8.6 microM vs. 4.1 microM), but the maximal phosphorylation rate was only 0.3% of the dTMP rate. These kinetic constants were consistent with the anabolism results and indicated that azidothymidine monophosphate is an alternative-substrate inhibitor of thymidylate kinase. This conclusion was reflected in the observation that cells incubated with azidothymidine had reduced intracellular levels of dTTP. IC50 (concentration of inhibitor that inhibits enzyme activity 50%) values were determined for azidothymidine triphosphate with HIV reverse transcriptase and with immortalized human lymphocyte (H9 cell) DNA polymerase alpha. Azidothymidine triphosphate competed about 100-fold better for the HIV reverse transcriptase than for the cellular DNA polymerase alpha. The results reported here suggest that azidothymidine is nonselectively phosphorylated but that the triphosphate derivative efficiently and selectively binds to the HIV reverse transcriptase. Incorporation of azidothymidylate into a growing DNA strand should terminate DNA elongation and thus inhibit DNA synthesis.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-214430, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-232189, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-2413459, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-2416116, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-4127027, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-4319233, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-58795, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6081184, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6083755, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6099709, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6200935, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6245517, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6282196, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6285704, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6310366, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-6406493, http://linkedlifedata.com/resource/pubmed/commentcorrection/2430286-7159465
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:volume
83
pubmed:owner
NLM
pubmed:authorsComplete
N
pubmed:pagination
8333-7
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Phosphorylation of 3'-azido-3'-deoxythymidine and selective interaction of the 5'-triphosphate with human immunodeficiency virus reverse transcriptase.
pubmed:publicationType
Journal Article