来自耶路撒冷蛾螺的血蓝蛋白与氧气的结合。II. 从配体-配体连接角度对协同性的解释。

Oxygen binding by hemocyanin from Levantina hierosolima. II. Interpretation of cooperativity in terms of ligand-ligand linkage.

作者信息

Shaklai N, Klarman A, Daniel E

出版信息

Biochemistry. 1975 Jan 14;14(1):105-8. doi: 10.1021/bi00672a018.

Abstract

Oxygen binding by hemocyanin from Levantina hierosolima was studied at pH 7.30, in solutions containing calcium in the concentration range 0-1 M. The binding was found to be cooperative, the degree of cooperativity being calcium concentration dependent. The dependence on calcium concentration of the affinity toward oxygen for both deoxygenated and oxygenated hemocyanin was interpreted in terms of two oxygen-linked calcium ions, one promoting and the other opposing oxygen binding. The results show that cooperativity may be fully explained on the basis of a coupling of the free energy of binding between calcium and oxygen.

摘要

在pH 7.30、钙浓度范围为0至1 M的溶液中，研究了来自耶路撒冷扁卷螺（Levantina hierosolima）的血蓝蛋白与氧气的结合情况。发现这种结合具有协同性，协同程度取决于钙浓度。根据两个与氧相连的钙离子来解释脱氧血蓝蛋白和氧合血蓝蛋白对氧的亲和力对钙浓度的依赖性，其中一个促进氧结合，另一个则起相反作用。结果表明，基于钙与氧结合自由能的耦合，可以充分解释协同性。