FIG. 3.

Exonuclease activity of T7 DNA polymerase. Either 2 nM M13 ³H-labeled dsDNA (A) or 1.2 nM M13 ³H-labeled ssDNA (B) was incubated in the reaction mixture described in Materials and Methods with the indicated concentration of either wild-type (wt) gp5/Trx or gp5-4N/Trx at 37°C for 10 min. Exonuclease activity was determined by measuring the radioactive DNA that bound to a DE-81 filter.