FIGURE 4.

Processing activity of recombinant human TDP1 on double-stranded substrate harboring 5′-phosphotyrosyl linkage with blunt end (Y40/40) or 2- (Y40/38), 4- (Y40/36), or 6-base (Y40/34) 5′-overhangs. A, the substrates were incubated with 1 μm TDP1 for the indicated time. P40 was used as marker. A gel representative of consistent results in independent experiments is shown. B, quantification of TDP1 processing activity from A (left). The error bars represent the S.E. (n = 3). A scheme of the DNA substrates used in A is shown (right). An asterisk indicates the internal radiolabeled site.