Peroxidase activity of in vitro-selected 2 '-amino RNAs

Peroxidase activities of RNAs containing 2'-amino groups, which were select ed as aptamers binding to N-methylmesoporphyrin IX, were investigated. Some clones promoted the oxidation reaction of 2,2'-azinobis(3-ethylbenzothiazo line-6-sulfonic acid) (ABTS) with hydrogen peroxide (H2O2) in the presence of iron(Ill)protoporphyrin (hemin), whereas others did not. Each of them ha d a different substrate specificity. One of the active clones promoted the oxidation of o-dianisidine and beta -nicotinamide adenine dinucleotide redu ced form (NADH) with H2O2 5 and 15 times faster than hemin only, respective ly. On the other hand, one clone that was inactive on oxidation of ABTS exh ibited the same level of activity on oxidation of o-dianisidine as that sho wn by the clone active on ABTS but no activity on NADH. By in vitro selecti on, we can produce various types of peroxidase-like non-natural RNAs. (C) 2 001 John Wiley & Sons, Inc.