How Well Should the Active Site and the Specific Recognition Be Defined for Proficient Catalyses? —Effective and Cooperative Polyphenol/Catechol Oxidation and Oxidative DNA Cleavage by a Copper(II)-Binding and H-bonding Copolymer

Vasiliki Lykourinou,[a] Ahmed I. Hanafy,[a,b] Giordano F. Z. da Silva,[a] Kirpal S. Bisht,[a] Randy W. Larsen,[a] Brian T. Livingston,[c] Alexander Angerhofer,[d] and Li-June Ming[a]*

[a]  Dr. Vasiliki Lykourinou, Dr. Ahmed I. Hanafy, Giordano F. Z. da Silva, Prof. Kirpal S. Bisht, Prof. Randy W. Larsen, and Prof. Li-June Ming*
Department of Chemistry
University of South Florida
4202 Fowler Avenue, Tampa, FL 33620, USA
Fax: (+) 01-813-974-1733

[b]  Dr. Ahmed I. Hanafy
Department of Chemistry, Faculty of Science
Al-Azhar University
Nasr City, Cairo, Egypt

[c]  Prof. Brian T. Livingston
Department of Biology
University of South Florida

[d]  Prof. Alexander Angerhofer
Department of Chemistry
University of Florida
Gainesville, FL 32611


Abstract: Despite the mainly inhomogeneous and unstructured nature of linear polymers, the CuII complex of a vinyl pyridine-acrylamide copolymer exhibits very efficient 2-electron catalysis toward the oxidation of catechol and derivatives to form quinones with and without 80 mM (0.27%) H2O2, showing remarkable (0.114–2.67) × 105 and (2.83–9.60) × 104-fold rate enhancements, respectively, in terms of first-order rate constant relative to auto-oxidation of the substrates in an aqueous environment under mild conditions. Metal-binding profiles suggest the presence of cooperativity in the catalysis. The oxidation catalysis is inhibited by the di-copper tyrosinase-specific kojic acid.   Moreover, electron paramagnetic resonance spectra reveal magnetic interaction of the CuII ions. Based on the results, the catalysis by this CuII-polymer seems to be consistent with the mechanism of type-3 di-copper oxidases.  This complex also shows effective single- and double-stranded DNA cleavage in the presence of 1.0% H2O2.  These studies suggest this CuII-polymer complex can serve as a unique “chemical nuclease” and a versatile chemical system for further exploration of Cu-oxygen chemistry.