为了阐明环结构和取代基对谷胱甘肽过氧化物酶-(GPx-)的影响,如脂肪族硒化物的抗氧化活性,合成了一系列具有可变环尺寸和极性官能团的水溶性环状硒化物,并评估了其抗氧化活性通过使用H 2 O 2和水中的谷胱甘肽(GSH)进行NADPH偶联测定,以及使用H 2 O 2和二硫苏糖醇(DTT红)进行NMR光谱分析)在甲醇中。在水中类似于GPx的活性,硒化物氧化的二级速率常数以及在水中计算出的HOMO能级之间发现了很强的相关性。结果支持了氧化过程是催化循环的速率决定步骤的结论。另一方面,对于在甲醇中观察到的活性没有获得这样的相关性。确定最佳环尺寸为五。取代基的类型(NH 2
Applications of Water-Soluble Selenides and Selenoxides to Protein Chemistry
作者:Michio Iwaoka、Fumio Kumakura
DOI:10.1080/10426500801901038
日期:2008.4.1
Two water-soluble organic selenides, 3,3'-selenodipropanonic acid and 2-selenanecarboxylic acid, were synthesized and reversibly converted to the corresponding selenoxides in deuterium oxide by the sequential treatment with stoichiometric amounts of hydrogen peroxide and then dithiothreitol. The antioxidative catalytic activity of 3,3'-selenodipropanonic acid was subsequently investigated by NMR spectroscopy in the reaction of hydrogen peroxide with dithiothreitol, cysteamine, and benzyl mercaptan in deuterated methanol. For all thiol substrates, the selenide exhibited the distinct catalytic activity. However, the activity was remarkably higher for the dithiol substrate (i.e., dithiothreitol). These results suggested that water-soluble selenides are good glutathione peroxidase mimics, in particular when polythiols are employed as the substrate. It was also suggested that water-soluble selenoxides are efficient oxidizing reagents for protein disulfide-bond formation.