ELECTRONIC EFFECTS ON THE BINDING OF DIOXYGEN AND CARBON-MONOXIDE TO HEMES
ELECTRONIC EFFECTS ON THE BINDING OF DIOXYGEN AND CARBON-MONOXIDE TO HEMES
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DOI：
10.1021/ja00406a043
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发表时间：
1981-01-01
影响因子：
15
通讯作者：
BERZINIS, AP
中科院分区：
文献类型：
--
作者：
TRAYLOR, TG;WHITE, DK;BERZINIS, AP
将螯合原血红素（具有近端咪唑共价连接的原血红素）与2个类似物进行比较，其中2个乙烯基被2个供电子的乙基或2个吸电子的乙酰基取代。在这个系列中，一氧化碳结合的动力学常数和平衡常数都没有明显变化。相反，二氧解离速率沿着乙基<乙烯基<乙酰基的顺序增加，二氧结合的平衡常数随之降低。这些结果是根据Fe.delta +- o .delta -键的偶极性质来讨论的。
Chelated protoheme (protoheme having a proximal imidazole covalently attached) is compared with 2 analogs in which the 2 vinyl groups are replaced by either 2 electron-donating ethyl groups or 2 electron-withdrawing acetyl groups. In this series neither the kinetic nor equilibrium constants for carbon monoxide binding vary appreciably. By contrast, the dioxygen dissociation rate increases along the series ethyl < vinyl < acetyl, with a consequent lowering of the equilibrium constant for dioxygen binding. These results are discussed in terms of the dipolar nature of the Fe.delta.+-OO.delta.- bond.