Reactive centers in alpha 2-macroglobulin.
Reactive centers in alpha 2-macroglobulin.
复制标题
α2-巨球蛋白的反应中心。
DOI：
10.1111/j.1749-6632.1983.tb18093.x
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发表时间：
1983
影响因子：
5.2
通讯作者：
Howard,JB
中科院分区：
文献类型：
--
作者：
Howard,JB
胺对有限数量的血浆蛋白的抑制作用已被认识到超过 60 这些蛋白质已被鉴定为％-巨球蛋白（a，M）、补体成分 C3 和补体成分 C4？-“这些蛋白质对低浓度简单胺的反应性是显着的，部分原因是胺是常见的生化化合物，并且在中性 pH 下是弱亲核试剂。一些早期报告表明，失活是可逆的，并且与蛋白质中的羰基官能团一致。最近，我们已经证明，对于a，M，该反应是特定谷氨酰残基的不可逆共价修饰。“”伴随着甲胺的掺入，半胱氨酰硫醇基团受到化学修饰。“！假设硫醇基团与反应性谷氨酰残基形成硫醇酯。硫醇酯也被用来解释% M在升高的条件下的异常裂解反应。温度。'！'我。" C3 和 C4 中描述了类似的反应，表明所有三种蛋白质具有共同的反应性。本文的目的是总结推定硫醇酯的证据并描述相关反应。
The inhibition of a limited number of plasma proteins by amines has been recognized for more than 60 These proteins have been identified as%-macroglobulin (a, M), complement component C3, and complement component C4?-'The reactivity of these proteins to low concentrations of simple amines is remarkable, in part, because amines are commonplace biochemical compounds and are weak nucleophiles at neutral pH. Some early reports indicated that the inactivation was reversible and consistent with a carbonyl functional group in the protein. Recently, we have shown for a, M that the reaction is an irreversible, covalent modification of a specific glutamyl residue."" Concomitant with methylamine incorporation, a cysteinyl thiol group is exposed to chemical modification."! The thiol group is postulated to form a thiolester with the reactive glutamyl residue. The thiolester also has been invoked to explain the anomalous cleavage reaction of% M at elevated temperatures.'!'I." Similar reactions have been described in C3 and C4 indicating that all three proteins have a common reactive It is the purpose of this paper to summarize the evidence for the putative thiolester and to describe the associated reactions.