Figure 5.

Within and between cell line variability in DNA repair enzyme activity of HepG2 and Caco-2 cells. (A) Uracil DNA glycosylase activity was higher in Caco-2 nuclear extract than HepG2 nuclear extract. (B) No significant differences were found in apurinic/apyrimidinic site incision activity between the two cell lines. (C) DNA polymerase activity was lower in Caco-2 nuclear extract than HepG2 nuclear extract. (D) DNA ligase activity was lower in Caco-2 nuclear extract than HepG2 nuclear extract. Bars indicate mean ± SD of six independent replicates. The symbols * and *** indicate significant differences between the enzyme activities of the cell lines at P < 0.05 and P < 0.001, respectively (based on two-tailed unpaired t-tests).