Hemoglobin, horseradish peroxidase, and heme-bovine serum albumin as biocatalyst for the oxidation of dibenzothiophene.
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.
Stachyra
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T
Laboratoire de Technologie Enzymatique, Centre National de La Recherche Scientifique, Université de Technologie de Compiegne, France.
Guillochon
D
D
Pulvin
S
S
Thomas
D
D
D002384:Catalysis; D006418:Heme / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide; D010084:Oxidation-Reduction; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012997:Solvents; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry*
D006454:Hemoglobins; D012997:Solvents; D013876:Thiophenes; D012710:Serum Albumin, Bovine; D006418:Heme; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C016366:dibenzothiophene