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Table 4 Steady state kinetic parameters for EFdA-TP and dATP incorporation by WT and K65R HIV-1 RTs

From: Hypersusceptibility mechanism of Tenofovir-resistant HIV to EFdA

Enzyme dNTP K m (μM) kcat(min-1) kcat/K m (min-1 · μM-1) Selectivitya Fold changeb
T d26 /P d18-P5       
WT RT dATP 2.38 ± 0.27 1.58 ± 0.12 0.66 1 1
  EFdA-TP 0.66 ± 0.04 3.26 ± 0.42 4.94 7.5
K65R RT dATP 5.99 ± 0.81 0.92 ± 0.14 0.15 1 0.8
  EFdA-TP 1.83 ± 0.34 1.74 ± 0.42 0.95 6.3
T d31 /P d18-P0       
WT RT dATP 0.33 ± 0.07 6.32 ± 0.14 19.15 1 1
  EFdA-TP 0.23 ± 0.01 4.73 ± 0.33 20.57 1.1
K65R RT dATP 0.42 ± 0.01 3.62 ± 0.71 8.62 1 1
  EFdA-TP 0.31 ± 0.02 3.07 ± 0.15 9.90 1.1
T d31A /P d21       
WT RT dATP 0.37 ± 0.08 3.64 ± 0.57 9.84 1 1
  EFdA-TP 0.19 ± 0.06 3.54 ± 0.44 18.63 1.9
K65R RT dATP 1.06 ± 0.11 3.68 ± 0.28 3.47 1 0.9
  EFdA-TP 0.53 ± 0.05 3.38 ± 0.29 6.38 1.8  
  1. Values are mean ± S.D. of two to four independent experiments and were determined from Michaelis-Menten equation using GraphPad Prism 4.
  2. aSelectivity is the ratio of the incorporation efficiency (kcat/K m ) of EFdA-TP over that of dATP ([kcat/K m ]EFdA-TP / [kcat/K m ]dATP).
  3. bFold Change is the ratio of the selectivity in K65R over the selectivity in WT RT.