A synthetic polymer selective for paraoxon was prepared by a molecular surface imprinting technique. We have combined molecular imprinting with the ability of histidine to chelate metal ions to create active centrum of phosphotriesterase on microbead surfaces. For this purpose, methacryloyl-histidine-copper(II) [MAH-Cu(II)] and methacryloyl-histidine-copper(II)-paraoxon [MAH-Cu(II)-paraoxon] metal chelating monomers were synthesized; paraoxon imprinted polymers were produced and the binding characteristics of the polymers were evaluated. The optimum pH was determined applying different pH values and the hydrolytic activity of phosphotriesterase was evaluated in the framework of Micheaelis-Menten kinetics. In addition, the values of maximal rate: V. (4.58 x 10(-2) mu M/min) and Micheaelis-Menten constant, K-m (1.28 x 10(-3) M), were obtained from Lineweaver-Burk plots for the imprinted polymeric catalyst. (c) 2005 Elsevier B.V. All rights reserved.