【摘要】 以ＣＡＴ＿（１２）为自旋探针，用ＥＳＲ自旋标记法测量了不同表面ｐＨ时酰化前后紫膜表面负电荷密度，以酰化所屏蔽的表面电荷数为标准，计算了表面ｐＨ４－１１时单位菌紫质紫膜两侧的总负电荷数。结果表明：表面ｐＨ５－９时为９，表面ｐＨ≥１０及表面ｐＨ＜５时增大。结果有力支持了膜表面５个二价阳离子结合位点的模型。更多还原

【Abstract】 The pH-dependent surface charge densities ofthe acetylated and the native purple membranewere determined by the ESR spin lablemethod. The spin probe is CAT₁₂. The num-ber of surface charges shieded by acetylationwas adapted as a criterion to calculate the sur-face charge numbers on both sides of the pur-ple membrane from surface PH 4─11. The re-sult shows that the total surface negativecharge numbers are 9 per bacteriorhodopsin atsurface PH 5─9 but increases both above sur-face PH 9 and below surface PH 5. It supportsstrongly the model based on five divalentcation binding sites on the surface of purplemembrane .更多还原