Dissing S, Romano L, Passow H
J Membr Biol. 1981;62(3):219-29. doi: 10.1007/BF01998167.
Up to a SCN- concentration of about 110 mM, the concentration dependence of SCN- equilibrium exchange in human red cell ghosts can be represented by the superimposition of two flux components. One component shows saturation kinetics, the other does not. The saturable component has an activation enthalpy of 105 kJ/mole, exhibits a trans acceleration by Cl- and can be inhibited by H2DIDS. The nonsaturable component has a much lower activation enthalpy of 33 kJ/mole, is slightly reduced in trans acceleration experiments with Cl- and insensitive to H2DIDS but susceptible to inhibition by phloretin. At SCN- concentrations exceeding 110 mM, the saturable component undergoes irreversible self inhibition while the nonsaturable component remains unaltered. The half saturation concentration of the saturable flux component increases with decreasing pH from 3.0 mM at pH 7.4 to 13.3 mM at pH 6.0. Over this pH range, the maximal flux is only slightly increased from 19 x 10(-12) to 22 x 10(-12) moles x cm-2 x sec-1. The nonsaturable flux component also increases slightly. In accordance with previous observations of Wieth (J. Physiol. (London) 207:563-580, 1970), we find that SCN- increases K+ and Na+ permeability. The induced cation-permeability is considerably smaller than the SCN- exchange and the latter does not show the paradoxical temperature dependence that is known to pertain to the former.
在硫氰酸盐（SCN⁻）浓度高达约110 mM时，人红细胞膜空壳中SCN⁻平衡交换的浓度依赖性可由两个通量成分叠加表示。一个成分呈现饱和动力学，另一个则不然。可饱和成分的活化焓为105 kJ/摩尔，表现出氯离子（Cl⁻）介导的转位加速作用，且可被二氢吲哚-2,4-二磺酸（H₂DIDS）抑制。不可饱和成分的活化焓低得多，为33 kJ/摩尔，在Cl⁻介导的转位加速实验中略有降低，对H₂DIDS不敏感，但易被根皮素抑制。在SCN⁻浓度超过110 mM时，可饱和成分会发生不可逆的自我抑制，而不可饱和成分保持不变。可饱和通量成分的半饱和浓度随pH降低而增加，从pH 7.4时的3.0 mM增加到pH 6.0时的13.3 mM。在此pH范围内，最大通量仅从19×10⁻¹²略微增加到22×10⁻¹²摩尔·厘米⁻²·秒⁻¹。不可饱和通量成分也略有增加。根据维特（Wieth）先前的观察结果（《生理学杂志》（伦敦）207:563 - 580，1970），我们发现SCN⁻增加钾离子（K⁺）和钠离子（Na⁺）的通透性。诱导的阳离子通透性远小于SCN⁻交换，且后者未表现出已知与前者相关的反常温度依赖性。
