Fig. 1.

Nucleotide incorporation by pol δ displays biphasic kinetics. Pol δ (60 nM) was incubated with the DNA substrate (150 nM), and dGTP (50 μM) for various reaction times up to 20 seconds. The solid line represents the best fit of the data to the burst equation with a k_obs for the fast exponential phase equal to 0.58 ± 0.08 s⁻¹ and an amplitude of the fast exponential phase equal to 37 ± 3 nM.