Preparation and catalytic performance of surfactant-manganese peroxidase-MnII ternary complex in organic media

A novel preparation method for surfactant-MnP-MnII ternary complex utilizing water-in-oil emulsions has been developed. The surfactant-MnP complex was spectroscopically characterized, strongly suggesting that the heme environment of the surfactant-MnP complex in benzene is identical to that of native MnP in the aqueous buffer. o-Phenylenediamine oxidation catalyzed by the surfactant-MnP-MnII ternary complex was performed in benzene. The ternary complex efficiently catalyzed the oxidation, and the complex was catalytically stable. Kinetic experiments revealed that the reaction mechanism was as follows: MnP is oxidized by H2O2 and the oxidized intermediate catalyzes the oxidation of MnII to MnIII and the latter, after complexed with malonate, readily oxidizes o-PDA inside the complex. Thus, the organic substrate o-PDA, but not MnIII, shuttled between the surfactant-MnP-MnII ternary complex and organic solvent.