Study on the intermediate in theo-phenylenediamine oxidative reaction using hemoglobin as a mimetic peroxidase in aqueous-organic two phase

Hemoglobin was used as a mimetic enzyme for peroxidase to catalyze the oxidative reaction of o-phenylenediamine with H₂O₂ which functioned as an oxidant. The relationship between physicochemical properties of the intermediate and enzymatic activity of hemoglobin was studied. Since the solubility of the intermediate in the reaction is higher in butanol phase than in water phase, the intermediate itself diffused from the aqueous phase to the butanol phase. The experimental results showed that the rate of product and the stability of intermediate were associated with the temperature and the pH value of the buffer. The formation rate of intermediate and half-life period reveal the maximal in pH7, nevertheless, the whole rate of the catalytic reaction is the greatest in pH5, which the ratio of the initial rate in final product formation compared to that intermediate formation is the greatest. Foundation item: Supported by the National Natural Science Foundation of China (No. 39770200) Biography: Li Hai-cheng (1960-), male, Ph. D candidate, Pyongyang, D. P. R. Korea, research direction; mimetic enzyme.