FIGURE 7.

Excision rate of the 3′ → 5′ exonuclease activity of wild-type hPol ϵ. A preincubated solution of wild-type hPol ϵ (150 nm) and DNA (15 nm) was rapidly mixed with Mg²⁺ (8 mm) for various reaction times. Remaining substrate was plotted as a function of time. The solid lines represent the best fit to Equation 2 (see “Experimental Procedures”). hPol ϵ catalyzed the excision of the primers of DNA substrates R0 (A) and R4 (B) at a rate of 0.86 ± 0.08 and 0.33 ± 0.02 s⁻¹, respectively.