Diphenyl diselenide has shown interesting biological activities in various free-radical-induced damage models and can be considered as a potential candidate drug against oxidative stress. Apart from its anti-oxidant activity, this compound can oxidize various thiols. However there are no detailed studies in the literature about the thiol oxidase-like activity of this compound against biologically significant mono and di-thiols with respect to various pH conditions. Keeping in mind the scarcity of data in this area of organochalcogen chemistry, we report for the first time the kinetics of thiol oxidation by diphenyl diselenide, which was carried out in a commonly used phosphate buffer, not only at physiological pH, but also at a number of acidic values. The relative reactivities of the different thiols with diphenyl diselenide were independent of the pKa of the thiol group, such that at pH 7.4, cysteine and dithiothreitol were the most reactive, while 2,3-dimercapto-1-propanesulfonic acid and glutathione were weakly reactive and extremely low reactivity was observed with dimercaptosuccinic acid. Rate of oxidation was dependent on the pH of the incubation medium. The results obtained will help us in the design of rational strategies for the safe pharmacological use of diphenyl diselenide.
二苯二
硒显示了在各种自由基诱导损伤模型中的有趣
生物活性,可以被视为抗氧化压力的潜在候选药物。除了其抗氧化活性外,该化合物还可以氧化多种
硫醇。然而,目前文献中尚无详细研究该化合物在不同pH条件下对
生物显著的单
硫醇和二
硫醇的
硫醇氧化酶样活性。鉴于该领域有机
硒化学数据的稀缺,我们首次报告了二苯二
硒对
硫醇氧化的动力学研究,该研究在常用的
磷酸盐缓冲液中进行,不仅在生理pH下,还在多个酸性值下进行。不同
硫醇与二苯二
硒的相对反应性与
硫醇基团的pKa无关,在pH 7.4时,半胱
氨酸和二
硫硫醇反应性最强,而2,3-二巯基-1-
丙烷磺酸和
谷胱甘肽反应性较弱,与二
巯基琥珀酸的反应性极低。氧化速率依赖于
培养基的pH。所获得的结果将有助于我们设计二苯二
硒安全药理学使用的合理策略。