Hemoglobin, horseradish peroxidase, and heme-bovine serum albumin as biocatalyst for the oxidation of dibenzothiophene

• DOI: 10.1007/bf02783567
• Publication Date: 2007-12-15T04:25:32Z
• Authors: Thérèse Stachyra; Didier Guillochom; Sylviane Pulvin; Daniel Thomas
• Keywords: 0303 health sciences; Serum Albumin, Bovine; Heme; Hydrogen Peroxide; Thiophenes; Catalysis; Hemoglobins; 03 medical and health sciences; Spectrophotometry; Solvents; Spectrophotometry, Ultraviolet; Oxidation-Reduction; Horseradish Peroxidase

Hemoglobin, horseradish peroxidase, and bovine serum albumin incubated heme-catalyzed the oxidation of dibenzothiophene into sulfoxide in the presence of hydrogen peroxide. This reaction was carried out in an aqueous buffer containing 25% of water-miscible organic solvents. The observation of this transient state of hemoproteins during sulfoxidation showed heme degradation. None of the compounds usually involved in a classical peroxidative activity mechanism were detected. Furthermore, this activity did not appear to be based on a Fenton-type reaction. The highest degrees of sulfoxidation were obtained with hemoglobin. Under the best conditions of reaction, 100% of dibenzothiophene were converted into dibenzothiophene sulfoxide by hemoglobin. Heat-denatured hemoproteins did keep their sulfoxidation activity. With hemoglobin, a kcat of 0.22 min-1 was determined. Nearly the same values were obtained with heat-denatured hemoglobin and bovine serum albumin-adsorbed heme. With horseradish peroxidase, only 4% of conversion was attained. This percentage could be slightly increased by using a less pure peroxidase or heat-denatured peroxidase.