Application of heme-containing biocatalysts for oxidation and determination of organosulfur compounds

The conditions of the oxidation of dibenzothiophene and aliphatic phenothiazines (promazine and chlorpromazine) in the presence of heme-containing biocatalysts (such as horseradish peroxidase and hemoglobin) have been optimized. It has been demonstrated that hemoglobin is an efficient catalyst for the fast and selective conversion of dibenzothiophene to the corresponding sulfoxide (yield is 91 ± 2% in 5 min); horseradish peroxidase is a more promising catalyst for the oxidation of phenothiazines. The effect of polar organic solvent (dimethyl sulfoxide) on the kinetics parameters of the reaction of oxidation of promazine in the presence of heme-containing biocatalysts has been studied. Procedures of determining phenothiazines based on spectrophotometric control of the rate of their oxidation have been developed. The applicable concentration ranges for the determination of promazine and chlorpromazine using horseradish peroxidase in aqueous medium were 10–100 μM and 10–200 μM respectively, and 20–500 μM for the determination of promazine in the presence of 10 vol % of dimethyl sulfoxide.