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. Author manuscript; available in PMC: 2011 May 4.
Published in final edited form as: Biochemistry. 2010 May 4;49(17):3545–3554. doi: 10.1021/bi100042b

FIGURE 2.

FIGURE 2

Effect of DNA primer/template concentration on the amplitude of the burst phase of DNA synthesis catalyzed by Pol δ4exo- or Pol δ3exo-. (A) Effect of an enzyme trap. The reaction shown in Fig. 1B (x′s) was repeated in the presence of an enzyme trap (0.5 mg/ml calf-thymus DNA). The trap abolished the slow phase of the reaction catalyzed by Pol δ4exo- (solid circles), and data was fit to equation 1 with the following parameters [ED] = 19.8 nM, kobs = 94 s-1, v= 0 nM/s (B) Single turnover reactions (see Experimental Procedures) containing Pol δ4exo- or Pol δ3exo- (20 nM p125), 500 μM dGTP, 0.5 mg/ml calf thymus DNA and the indicated amounts of [5′-32P]26merC/40mer. Product concentration ([P]) at 1 s, which reflects the burst amplitude ([ED]) of the reaction, is plotted versus DNA concentration and fit to equation 3 with a KDNA of 34 ± 5.4 nM for Pol δ4exo- and 35 ± 6.5 nM for Pol δ3exo-. Data for Pol δ4exo- and Pol δ3exo- are shown as filled and solid circles, respectively.