9-[2-(phosphonomethoxy)ethyl]adenine diphosphate (PMEApp) as a substrate toward replicative DNA polymerases α, δ, ε, and ε∗

Autor: Antonín Holý, Otová B, Gabriel Birkus, Ivan Votruba
Rok vydání: 1999
Předmět:
Zdroj: Biochemical Pharmacology. 58:487-492
ISSN: 0006-2952
DOI: 10.1016/s0006-2952(99)00118-5
Popis: The diphosphoryl derivative of the acyclic nucleotide phosphonate analog 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA), found previously to weakly inhibit DNA pol δ/proliferating cell nuclear antigen, was studied as a substrate for pol α, δ, e, and e∗. A comparison of the V max and K m for this derivative (PMEApp) and dATP demonstrated that the relative efficiency of the incorporation of this analog into the DNA chain is decreasing in the following order: pol δ ≃ pol e ≃ pol e∗ > pol α. Under the reaction conditions, this incorporation amounted to 4.4 to 0.7% of dAMP molecules. Similar K m values for PMEApp and dATP in pol e and pol e∗ catalyzed reactions revealed that proteolysis of the enzyme probably does not affect the dNTP binding site. The DNA polymerases tested were inhibited by the reaction product (PMEA terminated DNA chain) with similar K i / K m ratios (pol α 0.2; pol δ, 0.1; pol e 0.05; and pol e∗, 0.06). The associated 3′-5′-exonuclease activity of pol δ, e, and e∗ was able to excise PMEA from the 3′-OH end of DNA with a rate one order of magnitude lower than that of the dAMP residue.
Databáze: OpenAIRE