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The mechanism of phosphorylation of anti-HIV D4T by nucleoside diphosphate kinase.


Mol Pharmacol. 2000 May;57(5):948-53. Unique Identifier : AIDSLINE

The last step in the intracellular activation of antiviral nucleoside analogs is the addition of the third phosphate by nucleoside diphosphate (NDP) kinase resulting in the synthesis of the viral reverse transcriptase substrates. We have previously shown that dideoxynucleotide analogs and 3'-deoxy-3'-azidothymidine (AZT) as di- or triphosphate are poor substrates for NDP kinase. By use of protein fluorescence, we monitor the phosphotransfer between the enzyme and the nucleotide analog. Here, we have studied the reactivity of D4T (2',3'-dideoxy-2',3'-didehydrothymidine; stavudine) as di- (DP) or triphosphate (TP) at the pre-steady state. The catalytic efficiency of D4T-DP or -TP is increased by a factor of 10 compared with AZT-DP or -TP, respectively. We use an inactive mutant of NDP kinase to monitor the binding of a TP derivative, and show that the affinity for D4T-TP is in the same range as for the natural substrate deoxythymidine triphosphate, but is 30 times higher than for AZT-TP. Our results indicate that D4T should be efficiently phosphorylated after intracellular maturation of a prodrug into D4T-monophosphate.

JOURNAL ARTICLE Adenosine Triphosphate/METABOLISM Anti-HIV Agents/*METABOLISM Human HIV-1 Reverse Transcriptase/METABOLISM Kinetics Nucleoside-Diphosphate Kinase/*METABOLISM Phosphorylation Stavudine/*METABOLISM Support, Non-U.S. Gov't Thymine Nucleotides/METABOLISM Zidovudine/ANALOGS & DERIVATIVES/METABOLISM


Information in this article was accurate in July 30, 2000. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.