Activities of deoxyribozymes from the follow-up N20, N30, and N40 selections for DNA-catalyzed DNA hydrolysis. (A) PAGE image for each of the six new deoxyribozymes, showing representative timepoints (t = 30 s, 15 min, 2 h, and 20 h). Substrate (open arrowhead) and product (filled arrowhead) are marked. Incubation conditions: 70 mM HEPES, pH 7.5, 1 mM ZnCl2, 20 mM MnCl2 if indicated, and 150 mM NaCl at 37 °C. (B) Kinetic plots. kobs values are tabulated in Table S4.