作者:Ilia A. Dereven'kov、Sergei V. Makarov、Pavel A. Molodtsov、Anna S. Makarova
DOI:10.1002/kin.21430
日期:2021.1
studied the reaction between reduced riboflavin (RibH2) and selenocystine (Sec‐Sec), an oxidized form of Sec. The interaction between RibH2 and Sec‐Sec proceeded relatively slowly in comparison with its reverse reaction, that is, reduction of riboflavin (Rib) by Sec. The rate constant for the reaction between RibH2 and Sec‐Sec was (7.9 ± 0.1) × 10−2 M−1 s−1 (pH 7.0, 25.0°C). The reaction between Rib and
硒代半胱氨酸(Sec)是哺乳动物硫氧还蛋白还原酶(TrxR)的重要组成部分,它充当硫氧还蛋白(Trx)中二硫键断裂的亲核试剂。在TrxR中生成Sec还原态需要连续两个电子转移步骤,即:(i)从NADPH到黄素腺嘌呤二核苷酸,(ii)从黄素还原到二硫键Cys 59 -S-S-Cys 64,最后(iii)从Cys 59和Cys 64到硒代硫键Cys 497 -S-Se-Sec 498。在这项工作中,我们研究了还原型核黄素(RibH2)与硒代半胱氨酸(Sec-Sec)之间的反应,Sec-Sec是氧化形式的Sec。与RibH2和Sec-Sec之间的相互作用相比,它的逆反应(即Sec减少核黄素(Rib))的反应进行得相对缓慢。RibH2与Sec-Sec之间反应的速率常数为(7.9±0.1)×10 -2 M -1 s -1(pH 7.0,25.0°C)。Rib和Sec之间的反应通过两个步骤进行,即R