Reaction of nitric oxide with heme proteins and model compounds of hemoglobin.
Reaction of nitric oxide with heme proteins and model compounds of hemoglobin.
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DOI：
10.1021/bi00387a015
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发表时间：
1987-06
期刊：
影响因子：
2.9
通讯作者：
V. Sharma;T. Traylor;Robert T. Gardiner;H. Mizukami
中科院分区：
文献类型：
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作者：
V. Sharma;T. Traylor;Robert T. Gardiner;H. Mizukami
已经测量了一氧化氮与几种铁血红素蛋白和模型化合物的反应速率。NO结合率明显受远端组氨酸存在与否的影响。其中E7末端组氨酸已被谷氨酰胺取代的大象肌红蛋白与NO的反应速度比天然血红蛋白或肌红蛋白快500-1000倍。相比之下，抹香鲸和大象肌红蛋白的CO结合速率常数没有差异。血红蛋白的R和T状态的铁模型化合物的研究表明，它们的NO结合速率常数是类似的CO与相应的铁衍生物的组合所观察到的。最后的观察结果表明，在铁血红蛋白A的配体结合位点的轴向水分子的存在下，防止其在与NO的反应中表现出显着的协同性。
Rates for the reaction of nitric oxide with several ferric heme proteins and model compounds have been measured. The NO combination rates are markedly affected by the presence or absence of distal histidine. Elephant myoglobin in which the E7 distal histidine has been replaced by glutamine reacts with NO 500-1000 times faster than do the native hemoglobins or myoglobins. By contrast, there is no difference in the CO combination rate constants of sperm whale and elephant myoglobins. Studies on ferric model compounds for the R and T states of hemoglobin indicate that their NO combination rate constants are similar to those observed for the combination of CO with the corresponding ferro derivatives. The last observation suggests that the presence of an axial water molecule at the ligand binding site of ferric hemoglobin A prevents it from exhibiting significant cooperativity in its reactions with NO.