【摘要】 本文根据带正电荷自旋探针CAT₁₂在紫膜结合相和水相的分布,利用自旋探针顺磁共振（ESR）技术测定了Mg²⁺对紫膜表面电位的影响,我们的结果表明紫膜具有σ为3.02×10^-4Ch-arges/（?）²的表面电荷密度.据此σ用Gouy-Chapman理论计算得到Mg²⁺离子浓度与表面电位（（?）_i）的关系与实验结果极为一致,这表明离子通过表面电位的变化引起紫膜的表面pH值的改变从而影响紫膜的结构与功能,Mg²⁺对紫膜表面电位的影响明显地比K⁺要大,说明镁离子可能在紫膜的结构与功能中有更为重要的作用.更多还原

【Abstract】 The effect of mg2+ on surface potential changes of purple membrane wasdetermined by detecting the distribution of the positively charged, paramagnetic amphiphile probe CAT12 (4-(dodecylmethylammonium) -l-oxyl-2, 2, 6, 6-tetra-methylpiperdine iodine) in aqueous-free and membrane-bound phases. The result showed that surface charge densities σ of purple membrane was 3.02×10-4 charges/A2. The relation between concentration of Mg2+ and surface potential (Ψi) which is calculated from Gouy-Chapman theory is identical with that from experiment. The suggests the ions change the surface-pH with surface potential and then affect the stucture and function of purple membrane. The effect of Mg2+ on surface potentials of purple membrabe is greater than that of K+ . It means that Mg2+ probably plays a more important role in the structure and function of purple membrane.更多还原