Nuclease-like activity of a cyclic tetrameric schiff base (tetraanhydroaminobenzaldehyde) N-coordinated copper complex

Chemical nucleases are compounds that are able to bind to the surface of nucleic acids and are involved in the generation of free radicals which cleave nucleic acids. The aim of this study was to investigate the interaction of copper(II) tetrabenzo [b,f,j,n] [1,3,9,13] tetraazacyclohexadecine (Cu(TAAB)2+) with DNA and determine the DNase-like activity of this complex. Dichroic properties, electronic absorption and electrophoretical techniques were used to study the reaction of the complex with DNA. Cu(TAAB)2+ affected the dichroic properties and u.v. absorption of calf thymus DNA under anaerobic conditions. The anaerobic melting point of DNA was not affected in the presence of Cu(TAAB)2+. The hyperchromicity of DNA at 260 nm in the presence of Cu(TAAB)2+ with both ascorbic acid and oxygen was determined and compared with the known chemical nuclease Cu(phenantroline)2. Plasmid DNA in the presence of ascorbic acid and oxygen was effectively cleaved by Cu(TAAB)2+ in a concentration dependent manner. It is concluded that the Cu(TAAB)2+ complex is a potential chemical nuclease.