Cann J R, Stimpson D I
Biophys Chem. 1977 Sep;7(2):103-14. doi: 10.1016/0301-4622(77)80003-3.
A phenomenological theory of isoelectric focusing is formulated for rapidly reversible, ampholyte-induced macromolecular isomerization. The calculations reveal that such interactions can give well resolved, bimodal transient and equilibrium isoelectric focusing patterns in which the two peaks correspond to different chemical equilibrium compositions and not to separated isomers. The kinetics of approach to the equilibrium pattern are characteristically biphasic: During the first phase, which is controlled by the rate of migration of the isomers in the electric field, two peaks are positioned in the region between the isoelectric points of the two isomers; one of the peaks then grows slowly at the expense of the other with a diffusion-dominated rate. The kinetics are dependent upon the initial distribution of macromolecule in the isoelectric focusing column, and in certain cases only a single peak is apparent during the first phase. These findings have practical implications for unambiguous interpretation of isoelectric focusing patterns, furnish explanations for hitherto puzzling experimental observations, and provide theoretical insights required for application of isoelectric focusing to the detection and characterization of macromolecular interactions in general.
针对快速可逆的两性电解质诱导的大分子异构化现象，构建了一种等电聚焦的现象学理论。计算结果表明，这种相互作用可以产生分辨率良好的双峰瞬态和平衡等电聚焦模式，其中两个峰对应于不同的化学平衡组成，而非分离的异构体。达到平衡模式的动力学具有典型的双相性：在由异构体在电场中的迁移速率控制的第一阶段，两个峰位于两种异构体等电点之间的区域；然后其中一个峰以扩散主导的速率缓慢增长，同时另一个峰减小。动力学取决于大分子在等电聚焦柱中的初始分布，在某些情况下，第一阶段仅出现一个明显的峰。这些发现对于明确解释等电聚焦模式具有实际意义，为迄今令人困惑的实验观察结果提供了解释，并为将等电聚焦应用于一般大分子相互作用的检测和表征所需的理论见解提供了依据。
