Clarke R J
Division of Physical and Theoretical Chemistry, School of Chemistry, University of Sydney, New South Wales, Australia.
Adv Colloid Interface Sci. 2001 Jan 29;89-90:263-81. doi: 10.1016/s0001-8686(00)00061-0.
The dipole potential is an electrical potential within phospholipid membranes, which arises because of the alignment of dipolar residues of the lipids and/or water dipoles in the region between the aqueous phases and the hydrocarbon-like interior of the membrane. For a fully saturated phosphatidylcholine membrane, its value is believed to be in the range 220-280 mV, positive in the membrane interior. This results in an enormous electric field strength within the membrane of 10(8)-10(9) Vm(-1). The dipole potential is thus likely to have great significance in controlling the conformation of ion-translocating membrane proteins and so in regulating enzyme function. Because of its location within the membrane, quantification of the dipole potential is extremely difficult and presents a great challenge to the experimentalist and theoretician alike. Both electrical and spectroscopic methods developed for the determination of the dipole potential on lipid bilayers and monolayers are presented and possible causes for differences in the values derived are discussed.
偶极电势是磷脂膜内的一种电势，它是由于水相和膜类烃内部之间区域内脂质的偶极残基和/或水偶极的排列而产生的。对于完全饱和的磷脂酰胆碱膜，其值据信在220 - 280 mV范围内，在膜内部为正。这导致膜内产生10(8)-10(9) Vm(-1)的巨大电场强度。因此，偶极电势在控制离子转运膜蛋白的构象从而调节酶功能方面可能具有重要意义。由于其位于膜内，偶极电势的量化极其困难，对实验人员和理论人员都构成了巨大挑战。本文介绍了用于测定脂质双层和单层上偶极电势的电学和光谱学方法，并讨论了所得值存在差异的可能原因。
