Peroxidase-like catalytic activity of Mn³⁺-octabromo-tetrakis(4-sulfophenyl)porphine on linoleate hydroperoxide and its analytical application

To reveal an enzyme-like catalytic activity of metal-octabromo-tetrakis(sulfophenyl)porphines (M-OBPSs), their peroxidease-like catalytic activity on linoleate hydroperoxide (LOOH) were evaluated on the basis of dye-formation in the coloring reaction between N,N-diethylaniline and 4-aminoantipyrine that yields a quinoid-type dye. Among M-OBPSs tested, Mn³⁺-OBPS allowed to produce the largest amount of dye. The optimal conditions of the coloring reaction catalyzed by Mn³⁺-OBPS for the determination of LOOH were determined. A good linear calibration curve was obtained in the concentration range of 0.025-0.4 μmole LOOH with good reproducibility (coefficient of variance = 1.23%), suggesting that Mn³⁺-OBPS is a good artificial mimesis of the peroxidase for LOOH. In addition, Mn³⁺-OBPS was highly specific for LOOH even in the presence of cumene hydroxyperoxide or hydrogen peroxide. It was revealed that the peroxidase-like activity of Mn³⁺-OBTP is attributable to the redox cycle of Mn³⁺ ↔ Mn⁴⁺.