Hydrolysis of dinucleoside phosphates – mRNA 5′ cap analogues – promoted by a binuclear copper(II)–zinc(II) complex

The hydrolysis of a 5′ cap analogue, diadenosinyl-5′,5′-triphosphate (ApppA), and two dinucleoside monophosphates: adenylyl(3′,5′)adenosine (ApA) and uridylyl(3′,5′)uridine (UpU) promoted by an imidazolate-bridged heterobinuclear copper(II)–zinc(II) complex, Cu(II)-diethylenetriamino-μ-imidazolato–Zn(II)- tris(aminoethyl)amine trisperchlorate (denoted as Cu,Zn-complex in the followings) has been investigated. Kinetic measurements were performed in order to explore the effects of pH, the total concentration of the Cu,Zn-complex and temperature on the cleavage rate. The catalytic activity of the Cu,Zn-complex was quantified by pseudo-first-order rate constants obtained in the excess of the cleaving agent. The results show that the Cu,Zn-complex and its deprotonated forms have phosphoesterase activity and with ApppA the metal complex promoted cleavage takes place selectively within the triphosphate bridge.