Figure 4.

Substrate specificity of DNA polymerase α for incorporating the triphosphate forms of FTD, dUrd and FdUrd into the complement DNA strand at sites matching adenine (A), guanine (B), thymine (C), or cytosine (D). Substrates were incubated for 30 min at 37°C in reaction buffer containing a single-stranded DNA oligonucleotide hybridized to an FITC-labeled primer (0.1 μmol/l) and DNA polymerase α. After reactions were completed, the samples were denatured and electrophoresed on a denaturing acrylamide gel at 300 V for 3.5 h.