Unique cyanide adduct in human serum albumin: potential as a surrogate exposure marker.
Unique cyanide adduct in human serum albumin: potential as a surrogate exposure marker.
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DOI：
10.1021/tx100344e
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发表时间：
2011-04-18
影响因子：
4.1
通讯作者：
Aldous KM
中科院分区：
文献类型：
--
作者：
Fasco MJ;Stack RF;Lu S;Hauer CR 3rd;Schneider E;Dailey M;Aldous KM
氰化物 (CN = HCN + CN−) 是一种著名的毒物和神经毒物，在整个环境中普遍存在。尽管在过去的半个世纪中进行了大量的研究，但人们对其在亚致死暴露下导致不良健康结果的潜力知之甚少。 CN 暴露通常通过血液测定，但由于 CN 会快速代谢并从该区室中清除（t1/2 < 1 小时），因此在抽取血样进行分析之前通常会经过几个半衰期。这一变量，加上人群中非常狭窄的毒性指数和代谢多样性，使得对 CN 暴露的准确评估以及因此对可能的不利健康结果的任何预测都非常成问题。我们之前的研究表明，人血清白蛋白 (HSA) 中的 Cys-SCN 加合物有可能作为 CN 暴露的回顾性替代物。在这里，我们报告了通过 CN 与 HSA C 端 Cys558Cys567 二硫键反应形成的 Cys567 处稳定的 SCN 加合物的发现。用盐酸胍中的碱处理从人血清中纯化的 HSA，从迄今为止检查的所有样品中的 Cys567-SCN 部分释放出易于检测的、独特修饰的 C 末端 19 聚体肽。包含 HSA-Cys567-S13C15N 标记的内标允许在替代肽的选择性反应监测 (SRM) 中通过 LC-MS/MS 定量 Cys567-SCN 加合物，具有高灵敏度和良好的精度。 CN 在体外与 HSA 中的 Cys558Cys567 二硫键的反应是特异性的、快速的，并且在推定的生理相关范围内具有浓度依赖性。来自各种人类血清的数据证明了该加合物作为 CN 暴露的生物标志物的潜在用途。
Cyanide (CN = HCN + CN−) is a renowned poison and neurotoxicant that is prevalent throughout the environment. Despite a plethora of studies conducted over the last half century, relatively little is known of its potential to cause adverse health outcomes at sublethal exposures. CN exposure is normally determined from blood, but because CN is rapidly metabolized and cleared from this compartment (t1/2 < 1 h), it is common for several half-lives to have passed before blood samples are drawn for analysis. This variable, coupled with a very narrow toxic index and metabolic diversity within the human population, have rendered accurate assessment of CN exposure, and consequently any predictions of possible adverse health outcomes, highly problematic. Prior studies by us showed the potential of Cys-SCN adducts within human serum albumin (HSA) to act as retrospective surrogates of CN exposure. Here we report the discovery of a stable, SCN adduct at Cys567 formed by reaction of CN with the C-terminal Cys558Cys567 disulfide bond of HSA. Treatment of HSA purified from human serum with base in guanidine hydrochloride releases a readily detectable, uniquely modified, C-terminal-19 mer peptide from Cys567-SCN moieties in all the samples examined thus far. Inclusion of a HSA-Cys567-S13C15N labeled internal standard permits quantitation of the Cys567- SCN adduct by LC-MS/MS in Selective Reaction Monitoring (SRM) of the surrogate peptide with high sensitivity and good precision. Reaction of CN in vitro with the Cys558Cys567 disulfide bond in HSA is specific, rapid, and concentration dependent within a putative, physiologically-relevant range. Data from various human sera demonstrate the potential usefulness of this adduct as a biomarker of CN exposure.