Anomalous azide binding to metmanganomyoglobin.
Anomalous azide binding to metmanganomyoglobin.
复制标题
异常叠氮化物与高铁锰肌红蛋白结合。
DOI：
10.1021/bi00661a002
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发表时间：
1976
期刊：
影响因子：
2.9
通讯作者：
Q. Gibson
中科院分区：
文献类型：
--
作者：
B. Hoffman;Q. Gibson
metmananomyoglobin （MnIIIMb）与叠氮化物的反应呈现出一种新的模式，直接证明了其动力学复杂性。虽然动力学分析可能不是唯一的，但根据分光光度变化判断，即使有无限大的[N3-]，叠氮化物络合物也不能完全形成。这被解释为由于最终光谱可观察到的叠氮化物配合物和中间物质之间的平衡，中间物质的光谱与MnIIIMb本身的光谱没有本质上的不同。这两种形式的叠氮化物配合物在3℃时表现出大致相等的比例。我们提出这种中间体是一种弱的Mn3+叠氮化物配合物，其中金属离子保持在近端组氨酸的咪唑的平面外，但金属在“最终”配合物中朝向阴离子。
The reaction of metmanganomyoglobin (MnIIIMb) with azide presents a novel pattern with direct evidence for kinetic complexity. Although the kinetic analysis may not be unique, it appears that the azide complex cannot be fully formed, as judged by spectrophotometric changes, even with an infinitely great [N3-]. This is interpreted as resulting from an equilibrium between the final spectroscopically observable azide complex and an intermediate species whose spectrum is not substantially different from that of MnIIIMb itself. The two forms of the azide complex appear to exhibit roughly equal proportions at 3 degrees C. We propose that this intermediate is a weak Mn3+ -azide complex in which the metal ion remains out-of-plane toward the imidazole of the proximal histidine, but that the metal lies toward the anion in the "final" complex.