Stachyra T, Guillochon D, Pulvin S, Thomas D
Laboratoire de Technologie Enzymatique, Centre National de La Recherche Scientifique, Université de Technologie de Compiegne, France.
Appl Biochem Biotechnol. 1996 Jun;59(3):231-44. doi: 10.1007/BF02783567.
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.
血红蛋白、辣根过氧化物酶和牛血清白蛋白孵育的血红素在过氧化氢存在下催化二苯并噻吩氧化为亚砜。该反应在含有25%与水混溶有机溶剂的水性缓冲液中进行。在亚砜氧化过程中对血红素蛋白这种瞬态的观察表明血红素降解。未检测到通常参与经典过氧化物活性机制的任何化合物。此外，这种活性似乎不是基于芬顿型反应。血红蛋白实现了最高程度的亚砜氧化。在最佳反应条件下，血红蛋白将100%的二苯并噻吩转化为二苯并噻吩亚砜。热变性的血红素蛋白确实保持了它们的亚砜氧化活性。对于血红蛋白，测定的催化常数（kcat）为0.22分钟⁻¹。热变性血红蛋白和牛血清白蛋白吸附的血红素获得了几乎相同的值。对于辣根过氧化物酶，仅实现了4%的转化率。使用纯度较低的过氧化物酶或热变性过氧化物酶，该百分比可能会略有增加。
