Widdas W F, Baker G F
Department of Biology, Royal Holloway College, University of London, Egham, Surrey, Great Britain.
Cytobios. 1995;81(326):135-58.
When human red cells are first placed in isotonic media of low ionic strength there is a triphasic volume change. The initial shrinkage (phase A) starting immediately is followed by a rapid reflation (phase B). The final shrinkage (phase C) is slower and has more variable properties. The first two phases need Cl- and HCO3- and they have been shown to involve both the band 3 anion exchanger and the red cell carbonic anhydrase. Phase C is only seen when phase B is present. Both phase B and phase C were accelerated by the lower monohydric alcohols. With methanol the acceleration was maximal near 2M, thereafter inhibition developed. The hypothesis is advanced that phase C involves a permeability for bicarbonate which is independent of the band 3 anion exchanger, and which may be a dimer of carbonic anhydrase. The unique kinetics, the physiological significance, and implications of the special bicarbonate transport system are discussed.
当人类红细胞首次置于低离子强度的等渗介质中时，会发生三相体积变化。最初立即开始的收缩（A相）之后是快速的再膨胀（B相）。最后的收缩（C相）较慢且性质更具变异性。前两个阶段需要Cl-和HCO3-，并且已证明它们涉及带3阴离子交换蛋白和红细胞碳酸酐酶。只有当B相存在时才会出现C相。B相和C相都被低级一元醇加速。对于甲醇，在接近2M时加速最大，此后出现抑制作用。有人提出假说，C相涉及一种与带3阴离子交换蛋白无关的碳酸氢盐通透性，它可能是碳酸酐酶的二聚体。讨论了这种特殊碳酸氢盐转运系统的独特动力学、生理意义和影响。
