We have used an RNA/DNA chimera, referred to as embRNA, to study the t
ransesterification of RNA catalyzed by aqueous terpyridyl Cu(II). This
substrate is cleaved in only one position, but it contains the polyan
ionic charge and many of the metal binding sites of an RNA polymer. Th
e pH rate profile and substrate dependence of the reaction are reporte
d. Kinetic results are consistent with the active agent being the mono
hydroxy form of the Cu(II) complex. (C) 1997 Elsevier Science S.A.