This communication reports on electrochemical detection of thrombin based on labeling with osmium tetroxide bipyridine [OsO₄(bipy)]. Tryptophan amino acids can be labeled at the C−C‐double bond, and at least some tryptophan moieties are accessible for labeling in thrombin. Using the catalytic hydrogen signal from adsorptive stripping voltammetry performed on hanging mercury drop electrode, we could detect as little as 1.47 nM [OsO₄(bipy)]‐modified thrombin. We also tested the binding of [OsO₄(bipy)]‐modified thrombin with the classic thrombin binding aptamer (TBA) on gold electrodes. This preliminary study revealed that even after modification, a major part of the affinity was conserved, and that the aptamer self‐assembled monolayer (SAM) could be regenerated several times. Molecular simulations confirm that [OsO₄(bipy)]‐modified thrombin largely preserves the high binding affinity also of the alternative HD22 aptamer to thrombin, albeit at slightly reduced affinities due to steric hindrance when tryptophans 96 and 237 are labelled. Based on these simulations, compensatory modifications in the aptamer should result in significantly improved binding with labelled thrombin. This combined experimental‐computational approach lays the groundwork for the rational design of improved aptamer sensors for analytical applications.

中文翻译：

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通过四氧化Bi联吡啶标记并与金电极上的适体结合来测定凝血酶的伏安法。

该交流报道了基于四氧化os联吡啶[OsO ₄（bipy）]标记的凝血酶的电化学检测。色氨酸可以在CC双键处进行标记，并且至少一些色氨酸部分可以在凝血酶中进行标记。使用悬挂式汞滴电极上的吸附溶出伏安法中的催化氢信号，我们可以检测到低至1.47 nM [OsO ₄（bipy）]修饰的凝血酶。我们还测试了[OsO ₄（bipy）]-修饰的凝血酶，在金电极上具有经典的凝血酶结合适体（TBA）。这项初步研究表明，即使经过修饰，亲和力的主要部分也得以保留，并且适体自组装单分子膜（SAM）可以再生数次。分子模拟证实[OsO ₄（bipy）]-修饰的凝血酶在很大程度上保留了替代HD22适体与凝血酶的高结合亲和力，尽管色氨酸96和237被标记时由于位阻而使亲和力略有降低。基于这些模拟，适体的补偿性修饰应导致与标记的凝血酶的结合显着改善。这种组合的实验与计算方法为合理设计用于分析应用的适体传感器奠定了基础。