Oxidative and hydrolytic DNA cleavage by Cu(II) complexes of salicylidene tyrosine schiff base and 1,10 phenanthroline/bipyridine

Ternary Cu(II) complexes [Cu(II)(saltyr)(B)] (1,2), (saltyr = salicylidene tyrosine, B = 1,10 phenanthroline (1) or 2,2' bipyridine (2)) were synthesized and characterized by various techniques. The complexes exhibit square pyramidal (CuN3O2) geometry. CT-DNA binding studies revealed that the complexes show good binding propensity (K-b = 3.47 x 10(4) M-1 and 3.01 x 10(4) M-1 for 1 and 2, respectively). The role of these complexes in the oxidative and hydrolytic DNA cleavage was studied. The catalytic ability of 1 and 2 follows the order: 1 > 2. The rate constants for the hydrolysis of phosphodiester bond were determined as 2.80 h(-1) and 2.11 h(-1) for 1 and 2, respectively. It amounts to (0.58-0.77) x 10(8) fold rate enhancement compared to non-catalyzed DNA cleavage, which is significant. (C) 2010 Elsevier Ltd. All rights reserved.