Figure 3.

Activity of the E. coli dsUDG protein using as substrate ɛC-34/G (■), U-34/G (▴,) or T-19/G (•, Inset) as substrate. 5′-³²P-labeled duplex oligonucleotide containing ɛC-34/G (■), U-34/G (▴), or T-19/G (•) mismatches (1 pmol in 100-μl reaction mixture) was incubated with increasing amounts of pure dsUDG protein for different periods of time in the presence of the Fpg protein. The products of the reaction were analyzed and quantified as described in Fig. 2. Each point represents the initial velocity of the enzymatic reaction. For details see Materials and Methods. Note the difference of scales in the Inset.