FIGURE 1.

Single turnover determination of thymine excision by TDG. A, single-turnover time courses for the removal of T from the T:G mispair where the 3′-base pair is G:C (○) or 8-oxoG:C (□). B, single-turnover time courses for the removal of T from the T:G mispair where the 3′-base pair is T:A (○) or 8-oxoG:A (□). TDG (250 nm) was incubated with 50 nm DNA substrate (T/G-G/C, T/G-oxG/C, T/G-oxG/A, or T/G-T/A) at 37 °C. Products were isolated, quantified, and analyzed as described under “Experimental Procedures.” The data were fit to an exponential time course (N = G, solid lines; N = 8-oxoG, dashed lines). The results from several independent determinations are tabulated in Table 1.