Detail of "29706-85-2"

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Phosphorylation of 3'-azido-3'-deoxythymidine and selective interaction of the 5'-triphosphate with human immunodeficiency virus reverse transcriptase

Phosphorylation of 3'-azido-3'-deoxythymidine and selective interaction of the 5'-triphosphate with human immunodeficiency virus reverse transcriptase. Furman, Phillip A.; Fyfe, James A.; St. Clair, Marty H.; Weinhold, Kent; Rideout, Janet L.; Freeman, George A.; Lehrman, Sandra Nusinoff; Bolognesi, Dani P.; Broder, Samuel; et al. (Dep. Virol., Wellcome Res. Lab., Research Triangle Park, NC 27709, USA). Proc. Natl. Acad. Sci. U. S. A., 83(21), 8333-7 (English) 1986. CODEN: PNASA6. ISSN: 0027-8424. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) The thymidine analog 3'-azido-3'-deoxythymidine (azidothymidine) [30516-87-1] was previously shown to inhibit human immunodeficiency virus (HIV) replication effectively in the 50-500 nM range. In contrast, inhibition of the growth of uninfected human fibroblasts and lymphocytes was obsd.Several reagents with their cas registry numbers 50-89-5 and 92586-35-1 are used here. only at concns. above 1 mM. The nature of this selectivity was investigated. Azidothymidine anabolism to the 5'-mono- [29706-85-2], -di- [106327-93-9], and -triphosphate [106327-94-0] derivs. 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 (￡5 mM and ￡2 mM, resp.). Cytosolic thymidine kinase (EC 2.7.1.21) [9002-06-6] was responsible for phosphorylation of azidothymidine to its monophosphate. Purified thymidine kinase catalyzed the phosphorylations of thymidine [50-89-5] and azidothymidine with apparent Km values of 2.9 mM and 3.0 mM. 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) [9014-43-1]. The apparent Km value for azidothymidine monophosphate was 2-fold greater than the value for dTMP [365-07-1] (8.6 mM vs. 4.1 mM), but the maximal phosphorylation rate was only 0.3% of the dTMP rate. These kinetic consts. 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 cell incubated with azidothymidine had reduced intracellular levels of dTTP [365-08-2]. IC50 (concn. of inhibitor that inhibits enzyme activity 50%) values were detd. for azidothymidine triphosphate with reverse transcriptase [9068-38-6] and with immortalized human lymphocyte (H9 cell) DNA polymerase [9012-90-2] a . Azidothymidine triphosphate competed about 100-fold better for the HIV reverse transcriptase than for the cellular DNA polymerase a. These results suggest that azidothymidine is nonselectively phosphorylated but that the triphosphate deriv. 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. These results may have relevance to the antiviral action mechanism for azidothymidine. .

The Crystal Structure of Mycobacterium tuberculosis Thymidylate Kinase in Complex with 3'-Azidodeoxythymidine Monophosphate Suggests a Mechanism for Competitive Inhibition

The Crystal Structure of Mycobacterium tuberculosis Thymidylate Kinase in Complex with 3'-Azidodeoxythymidine Monophosphate Suggests a Mechanism for Competitive Inhibition. Fioravanti, Emanuela; Adam, Virgile; Munier-Lehmann, Helene; Bourgeois, Dominique (LCCP, UMR 5075, IBS-CEA/CNRS/UJF, Grenoble 38027, Fr.In this study， 365-07-1 and 29706-85-2 are also used.). Biochemistry, 44(1), 130-137 (English) 2005 American Chemical Society. CODEN: BICHAW. ISSN: 0006-2960. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Section cross-reference(s): 75 Tuberculosis (TB) is the primary cause of mortality among infectious diseases. Mycobacterium tuberculosis thymidylate kinase (TMPKMtub) catalyzes the ATP-dependent phosphorylation of deoxythymidine 5'-monophosphate (dTMP). Essential to DNA replication, this enzyme represents a promising target for developing new drugs against TB, because the configuration of its active site is unique within the TMPK family. Indeed, it has been proposed that, as opposed to other TMPKs, catalysis by TMPKMtub necessitates the transient binding of a magnesium ion coordinating the phosphate acceptor. Moreover, 3'-azidodeoxythymidine monophosphate (AZTMP) is a competitive inhibitor of TMPKMtub, whereas it is a substrate for human and other TMPKs. Here, the crystal structures of TMPKMtub in complex with deoxythymidine (dT) and AZTMP were detd. to 2.1 and 2.0 ? resoln., resp., and suggest a mechanism for inhibition. The azido group of AZTMP perturbs the induced-fit mechanism normally adopted by the enzyme. Magnesium is prevented from binding, and the resulting electrostatic environment precludes phosphoryl transfer from occurring. Our data provide a model for drug development against tuberculosis. .