Figure 6.

Pulse-chase and pulse-quench experiment at 56°C. A preincubated solution of Dpo4 (30 nM) and unlabeled D-1 (30 nM) was mixed with [α-³²P]-dTTP (40 μM) for time intervals ranging from 0.02 to 2 s. The reactions in these two experiments were either quenched directly with 1 M HCl (pulse-quench) or chased with 2.5 mM unlabeled dTTP (pulse-chase) for 15 s, followed by an HCl quench. Both experiments were fit to the burst equation [Equation (3)] yielding amplitudes of 26.9 ± 1.8 nM and 23.3 ± 1.3 nM, for the pulse-quench (open circles) and pulse-chase (filled circles) experiments, respectively.