FIGURE 3.
Dependence of 2′-PO4 and 3′-PO4 removal on CthTpt1 concentration. Tpt1 reaction mixtures (10 µL) containing 100 mM Tris-HCl, pH 7.5, 0.2 µM (2 pmol) 5′ 32P-labeled 10-mer pRNA2′p, or pRNA3′p substrates (shown at top), 1 mM NAD+, and CthTpt1 as specified were incubated at 37°C for 30 min. The products were analyzed by urea-PAGE. The extents of product formation, quantified as described in Figure 2, are plotted as a function of input enzyme. Each datum is the average of three independent titration experiments ±SEM.