Pertaining to our report “Cleavage of an amide bond by a ribozyme” (13 Jan. 1995, p. 237) ([1][1]), we recently obtained data demonstrating a second reaction pathway superimposed on the amide cleavage reaction. The second pathway involves two successive phosphoester transfer reactions: first, miscleavage by the ribozyme at a DNA phosphoester adjacent to the amide linkage ([1][1], figure 2); second, attack by the 3′ hydroxyl of the miscleavage product at a phosphate immediately preceding a nonencoded nucleotide that is present at the 3′ terminus of a small proportion of ribozyme molecules that are produced by in vitro transcription. The resulting ribonucleoside-terminated product has nearly identical electrophoretic mobility compared with the amide-terminated product of the amide cleavage reaction when analyzed in a denaturing polyacrylamide gel at pH 8.3. The two products can be separated by polyacrylamide gel electrophoresis at pH 6.5, revealing that the second pathway dominates over amide bond cleavage. The rate of RNA-catalyzed amide cleavage is about 50-fold slower than we reported, thus representing only about a 102-fold rate acceleration when compared with the uncatalyzed reaction. The amide- and ribonucleoside-terminated products are derivatized with sulfosuccinimidyl-6-(biotinamido) hexanoate at approximately the same rate when incubated at pH 8.5 ([1][1], figure 3). The amine-, but not the ribonucleoside-terminated product is reactive with ninhydrin and can be derivatized with dansyl chloride, in accordance with the behavior of the authentic amine-terminated compound. The ribonucleoside-terminated product can be converted to an all-deoxynucleotide molecule, one residue shorter in length, by oxidation of the 2′,3′-diol to a dialdehyde and subsequent β-elimination. 1. 1.[↵][2] 1. X. Dai, 2. A. De Mesmaeker, 3. G. F. Joyce , Science 267, 237 (1995). [OpenUrl][3][Abstract/FREE Full Text][4] [1]: #ref-1 [2]: #xref-ref-1-1 View reference 1. in text [3]: {openurl}?query=rft.jtitle%253DScience%26rft.stitle%253DScience%26rft.issn%253D0036-8075%26rft.aulast%253DDai%26rft.auinit1%253DX.%26rft.volume%253D267%26rft.issue%253D5195%26rft.spage%253D237%26rft.epage%253D240%26rft.atitle%253DCleavage%2Bof%2Ban%2Bamide%2Bbond%2Bby%2Ba%2Bribozyme%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fscience.7809628%26rft_id%253Dinfo%253Apmid%252F7809628%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [4]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6Mzoic2NpIjtzOjU6InJlc2lkIjtzOjEyOiIyNjcvNTE5NS8yMzciO3M6NDoiYXRvbSI7czoyMzoiL3NjaS8yNzIvNTI1OC8xNS43LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==