Selenenyl iodide: a new substrate for mammalian thioredoxin reductaseElectronic supplementary information (ESI) available: additional data. See http://www.rsc.org/suppdata/ob/b3/b302220j/
作者:Govindasamy Mugesh、Lars-Oliver Klotz、Wolf-Walther du Mont、Katja Becker、Helmut Sies
DOI:10.1039/b302220j
日期:——
Areneselenenyl iodide stabilised by internal chelation has been synthesized and evaluated as a substrate of thioredoxin reductase (TrxR). The reactivity of TrxR obtained from human placenta towards selenenyl iodide was found to be much higher than that of the E. coli enzyme, indicating the essential nature of a selenocysteine residue in the active site of the human enzyme. The addition of thioredoxin (Trx) significantly enhanced the TrxR-catalysed reduction of selenenyl iodide 1. These studies on the reduction of a selenenyl iodide by the thioredoxin system suggest that stable selenenyl iodides could be new substrates for human TrxR. The Trx system could act as a cofactor for iodothyronine deiodinase by reducing the selenenyl iodide intermediate in the second-half of the deiodinase catalytic cycle to regenerate the active site. The TrxR-catalysed reduction of 1 was not inhibited by the anti-thyroid drug, PTU, suggesting that the involvement of the Trx system in the deiodinase cycle may be responsible for the insensitivity of certain deiodinases towards clinically useful thiourea drugs.
我们合成了通过内部螯合稳定的烯硒碘化物,并将其作为硫代还原酶(TrxR)的底物进行了评估。研究发现,从人类胎盘中提取的 TrxR 对硒碘化物的反应活性远高于大肠杆菌酶,这表明人类酶活性位点中的硒半胱氨酸残基是必不可少的。加入硫代氧化酶(Trx)后,TrxR 催化的碘化硒还原作用明显增强 1。这些关于硫氧还蛋白系统还原硒碘化物的研究表明,稳定的硒碘化物可能是人类 TrxR 的新底物。Trx 系统可以作为碘甲腺氨酸脱碘酶的辅助因子,在脱碘酶催化周期的后半段还原硒基碘化物中间体,以再生活性位点。抗甲状腺药物 PTU 不抑制 TrxR 催化的 1 的还原,这表明 Trx 系统参与脱碘酶循环可能是某些脱碘酶对临床有用的硫脲类药物不敏感的原因。