How do biological systems discriminate among physically similar ions?
How do biological systems discriminate among physically similar ions?
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生物系统如何区分物理相似的离子？
DOI：
10.1002/jez.1401940116
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
Jared M. Diamond
中科院分区：
文献类型：
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作者：
Jared M. Diamond
本文回顾了理解生物系统如何如此显着地区分物理相似离子（尤其是碱金属阳离子）的历史。对离子选择性的定性规律（“允许的序列”）和定量规律（“选择性等温线”）的认识首先来自对离子交换剂和玻璃电极的研究，然后是对酶和细胞膜等生物系统的研究，以及最近对掺杂模型孔和载体的脂质双层的研究。离子的辨别取决于静电力和空间力。对完整生物膜的“黑匣子”研究在某些情况下提供了有关实际生物孔和载体结构的分子线索。当前的主要问题涉及这些分子的提取；如何做到这一点，实现它后该怎么做，以及它如何（以及是否）与膜功能的核心问题相关。对膜内速率势垒、电压依赖性（“可兴奋”）传导通道以及日益复杂的模型系统和生物膜的研究预计很快会取得进一步进展。
This paper reviews the history of understanding how biological systems can discriminate so strikingly among physically similar ions, especially alkali cations. Appreciation of qualitative regularities ("permitted sequences") and quantitative regularities ("selectivity isotherms") in ion selectivity grew first from studies of ion exchangers and glass electrodes, then of biological systems such as enzymes and cell membranes, and most recently of lipid bilayers doped with model pores and carriers. Discrimination of ions depends on both electrostatic and steric forces. "Black-box" studies on intact biological membranes have in some cases yielded molecular clues to the structure of the actual biological pores and carriers. Major current problems involve the extraction of these molecules; how to do it, what to do when it is achieved, and how (and if) it is relevant to the central problems of membrane function. Further advances are expected soon from studies of rate barriers within membranes, of voltage-dependent ("excitable") conducting channels, and of increasingly complex model systems and biological membranes.