Release of 32P-labeled DNA (0.02 μM) from RFC (0.016 μM) was measured over time in the presence of 1 μM unlabeled DNA chase by nitrocellulose membrane filtration assays, as described under “Experimental Procedures.” A, 32P-labeled primer-template (●), 32P-labeled ssDNA (□), and 32P-labeled dsDNA (△) chased with excess unlabeled self as competitor. The dissociation rates are 0.025 ± 0.003 s−1, ≥0.2 s−1, and ≥0.2 s−1, respectively. B shows that if 32P-labeled primer-template is chased with excess unlabeled ssDNA (□) or dsDNA (△), the RFC·primed DNA complex persists over time, in contrast to the chase with unlabeled primer-template DNA (●).