HISTIDINE RESIDUE IN THE ACTIVE CENTRE OF RIBONUCLEASE .1. SPECIFIC REACTION WITH BROMOACETIC ACID
HISTIDINE RESIDUE IN THE ACTIVE CENTRE OF RIBONUCLEASE .1. SPECIFIC REACTION WITH BROMOACETIC ACID
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DOI：
10.1016/s0022-2836(59)80016-4
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发表时间：
1959-01-01
影响因子：
5.6
通讯作者：
STEIN, WD
中科院分区：
文献类型：
--
作者：
BARNARD, EA;STEIN, WD
溴乙酸很容易与核糖核酸酶反应，形成一种无活性的衍生物，其中在pH 7时，每个酶分子都引入了一个羧甲基。酶中唯一被取代的残基是分子中四个组氨酸之一。这种组氨酸与溴乙酸的反应速率远大于游离组氨酸，因此酶中的残基被激活。与溴乙酸的反应大大减慢，在胞苷酸，酶的竞争性抑制剂的存在下，这表明有关的组氨酸残基位于酶的活性中心。
Bromoacetic acid reacts readily with ribonuclease to form an inactive derivative in which, at pH 7, one carboxy-methyl group has been introduced per molecule of enzyme. The sole residue in the enzyme so substituted is shown to be one of the four histidines in the molecule. The rate of reaction of this histidine with bromoacetic acid is far greater than that of free histidine, the residue in the enzyme being, therefore, activated. The reaction with bromoacetic acid is slowed down greatly in the presence of cytidylic acid, a competitive inhibitor of the enzyme, suggesting that the histidine residue concerned is situated in the active centre of the enzyme.