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Fig. 3.12 Adenine-dependent hairpin ribozymes (ADHR). Arrowheads: cleavage sites. Gray dots: degenerated (mutated) sites. Vertical bars: separation between the primer binding region and the ribozyme sequence.

Recently, Tsukiji et al. (2004) reported a ribozyme that exhibits activity analogous to alcohol dehydrogenase (ADH). The ADH ribozyme was selected in vitro from a pool of random RNA sequences in the presence of NAD+ and Zn2+, based on the ability to convert a benzyl alcohol derivative to the corresponding aldehyde that was covalently attached to the 5' end of the RNA pool. In fact, the ribozyme oxidizes the benzyl alcohol to benzaldehyde in an NAD+ and Zn2+-dependent manner, with a rate acceleration at least 7 orders of magnitude higher than the uncatalyzed reaction.

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