Kachalova G S, Lanina N F, Evtodienko V U, Botin A S, Shlyapnikova E A, Morozov V N
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region, Russia.
Biophys Chem. 1996 May 13;60(1-2):1-16. doi: 10.1016/0301-4622(96)00007-5.
Micromethods for measurements of electric conductivity, transference numbers and concentrations of inorganic ions within immobilized protein crystals have been developed and applied to study tetragonal lysozyme crystals cross-linked with glutaraldehyde. Donnan equilibria and mobilities of ions in this crystal were calculated using the data of these methods and the data of crystal pH titration. Taken together these results characterize the lysozyme crystal as an ion exchanger whose electrical properties and ion composition differ greatly from those of the external solution. Although anions transfer most of the current in the crystals, anion mobility is considerably lower than that of cations. Mobility of all ions in the crystal is considerably lower than in solution (3.5-50 times for cations and 120-330 times for anions) and depends on steric restrictions and charges of both ions and lysozyme molecules. Similar features in behavior of crystalline and biological channels are discussed.
已经开发出用于测量固定化蛋白质晶体内电导率、迁移数和无机离子浓度的微方法，并将其应用于研究用戊二醛交联的四方溶菌酶晶体。利用这些方法的数据以及晶体pH滴定数据，计算了该晶体中离子的唐南平衡和迁移率。综合这些结果表明，溶菌酶晶体是一种离子交换剂，其电学性质和离子组成与外部溶液有很大差异。尽管阴离子在晶体中传导大部分电流，但阴离子迁移率明显低于阳离子。晶体中所有离子的迁移率都明显低于溶液中的迁移率（阳离子低3.5至50倍，阴离子低120至330倍），并且取决于离子和溶菌酶分子的空间位阻和电荷。文中讨论了晶体通道和生物通道行为的相似特征。
