Chang R S, Lotti V J, Keegan M E
Biochem Pharmacol. 1982 May 15;31(10):1903-6. doi: 10.1016/0006-2952(82)90495-6.
Dithiothreitol (DTT), a disulfide reducing agent, significantly decreased specific (( 3H]angiotensin II binding to membrane-bound and solubilized bovine adrenal cortical receptors. Scatchard analysis indicated a reduction in the maximum number of membrane-bound binding sites without change in affinity. The effect of DTT on membrane-bound receptors was readily reversed by the sulfhydryl oxidizing agent, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), indicating that its action upon specific[3H]angiotensin II binding is mediated via reduction of disulfide bonds rather than other properties of this agent. Preincubation of the membranes with unlabeled angiotensin II, but not its biologically inactive precursor angiotensin I, protected the receptor from deactivation by DTT. The data provide evidence that disulfide bonds essential for[3H]angiotensin II receptor binding in bovine adrenal cortex are located at, or near, the active sites of the receptor.
二硫苏糖醇（DTT）是一种二硫键还原剂，它能显著降低特异性[³H]血管紧张素II与膜结合及可溶的牛肾上腺皮质受体的结合。Scatchard分析表明膜结合位点的最大数量减少，而亲和力不变。巯基氧化剂5,5'-二硫代双（2-硝基苯甲酸）（DTNB）可轻易逆转DTT对膜结合受体的作用，这表明其对特异性[³H]血管紧张素II结合的作用是通过二硫键的还原介导的，而非该试剂的其他特性。用未标记的血管紧张素II（而非其无生物活性的前体血管紧张素I）对膜进行预孵育，可保护受体不被DTT失活。这些数据提供了证据，表明牛肾上腺皮质中[³H]血管紧张素II受体结合所必需的二硫键位于受体的活性位点或其附近。
