Cleavage analyzed at 40 μM RNA each strand; 2 mM MgCl2, 100 mM KCl, 30 mM HEPES, pH 7.5, 23 C. R 37-nt ribozyme, S 19-nt substrate; C1 and C2, 14-nt and 5-nt cleavage products. HPLC conditions: Dionex DNAPac colum (4 × 250 mm), 80 C, 1 mL min−1, 0–60% buffer B in 45 min. Buffer A: Tris–HCl (25 mM), urea (6 M), pH 8.0. Buffer B: Tris–HCl (25 mM), urea (6 M), NaClO4 (0.5 M), pH 8.0.