The effect of potassium chloride on the Bohr effect of human hemoglobin.
The effect of potassium chloride on the Bohr effect of human hemoglobin.
复制标题
氯化钾对人血红蛋白玻尔效应的影响。
DOI：
10.1016/s0021-9258(19)41818-8
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
G. van Os
中科院分区：
文献类型：
--
作者：
H. Rollema;S. de Bruin;L. Janssen;G. van Os
在各种KCl浓度（0.1至2.0 M）下测量配体和非配体血红蛋白的正常和微分滴定曲线。在此KCl浓度范围内，脱氧血红蛋白的曲线未显示可滴定组的盐诱导pK变化。在相同的盐浓度范围内，氧合血红蛋白显示出滴定行为的显着变化，这只能通过盐诱导的某些可滴定基团的pK增加来解释。这些结果表明，高浓度中性单价盐对碱性玻尔效应的抑制不是由脱氧血红蛋白中盐桥的减弱引起的，而是由于氯离子与氧合血红蛋白的相互作用。在不同KCl浓度下测量玻尔效应表明，在低氯离子浓度（5 × 10-3 M）下，碱性玻尔效应小于0.1 M浓度下的效应。这一观察结果表明，在0.1 M的氯离子浓度下，碱性玻尔效应的一部分是由于氯离子与血红蛋白的相互作用。此外，在低浓度的氯离子的酸玻尔效应几乎消失。这一结果表明，部分酸玻尔效应来自氯离子与氧合血红蛋白的相互作用。玻尔效应对氯离子浓度的依赖性可以通过假设氯离子与氧合血红蛋白和脱氧血红蛋白特异性结合来解释，其中脱氧血红蛋白具有最高的亲和力。
The normal and differential titration curves of liganded and unliganded hemoglobin were measured at various KCl concentrations (0.1 to 2.0 M). In this range of KCl concentrations, the curves for deoxyhemoglobin showed no salt-induced pK changes of titratable groups. In the same salt concentration range oxyhemoglobin showed a marked change in titration behavior which could only be accounted for by a salt-induced increase in pK of some titratable groups. These results show that the suppression of the alkaline Bohr effect by high concentrations of neutral univalent salt is not caused by a weakening of the salt bridges in deoxyhemoglobin but is due to an interaction of chloride ions with oxyhemoglobin. Measurements of the Bohr effect at various KCl concentrations showed that at low chloride ion concentration (5 times 10-3 M) the alkaline Bohr effect is smaller than at a concentration of 0.1 M. This observation indicates that at a chloride ion concentration of 0.1 M, part of the alkaline Bohr effect is due to an interaction of chloride ions with hemoglobin. Furthermore, at low concentrations of chloride ions the acid Bohr effect has almost vanished. This result suggests that part of the acid Bohr effect arises from an interaction of chloride ions with oxyhemoglobin. The dependence of the Bohr effect upon the chloride ion concentration can be explained by assuming specific binding of chloride ions to both oxy- and deoxyhemoglobin, with deoxyhemoglobin having the highest affinity.