Biochemistry of protein-isocyanate interactions: a comparison of the effects of aryl vs. alkyl isocyanates.
Biochemistry of protein-isocyanate interactions: a comparison of the effects of aryl vs. alkyl isocyanates.
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蛋白质-异氰酸酯相互作用的生物化学：芳基异氰酸酯与烷基异氰酸酯的影响比较。
DOI：
10.1289/ehp.87725
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发表时间：
1987-06
影响因子：
10.4
通讯作者：
中科院分区：
文献类型：
--
作者：
除了在聚氨酯和农药工业中的应用外，异氰酸酯已被证明是探索蛋白质结构的有用探针。本文重点关注异氰酸酯的三个方面：其广泛的反应性、与胆碱酯酶的可逆相互作用以及烷基和芳基异氰酸酯的相对水解速率。讨论了异氰酸酯的广泛反应性以及丝氨酸和巯基酯酶的亲和标记。亲和标记研究的扩展包括对异氰酸甲酯对胆碱酯酶的抑制的分析，表明异氰酸甲酯不是任何胆碱酯酶的有效抑制剂。烷基异氰酸酯对胆碱酯酶的抑制表现出随着烷基链长度的减少而特异性降低的模式。异氰酸酯对胆碱酯酶的抑制作用是可逆的，在生理 pH 值下可达到最大逆转率。这种逆转是异氰酸酯与巯基反应的特征。最后，蛋白质的亲和标记必须成功地与水溶液中异氰酸酯的水解竞争。异氰酸烷基酯的水解速度明显慢于异氰酸芳基酯的水解速度。
In addition to their use in the polyurethane and pesticide industries, isocyanates have proven to be useful probes for the exploration of protein structure. This paper focuses on three aspects of isocyanates: their broad reactivity, their reversible interaction with cholinesterases, and the relative hydrolysis rates of alkyl and aryl isocyanates. The broad reactivity of isocyanates as well as the demonstrated affinity labeling of serine and sulfhydryl esterases are discussed. Extension of the affinity labeling studies to include the analysis of the inhibition of cholinesterases by methyl isocyanate shows that methyl isocyanate is not an effective inhibitor of any of the cholinesterases. The inhibition of cholinesterases by alkyl isocyanates shows a pattern of decreased specificity with decreased alkyl chain length. The inhibition of cholinesterases by isocyanates is shown to be reversible, with a maximum rate of reversal seen at physiological pH. This reversal is characteristic of the reaction of an isocyanate with a sulfhydryl group. Finally, the affinity labeling of proteins must compete successfully with the hydrolysis of isocyanates in aqueous solution. The hydrolysis of alkyl isocyanates is shown to be significantly slower than that of the aryl isocyanates.