【摘要】 本文报道用荧光偏振及顺磁共振两种方法研究Mg²⁺及其它二价金属离子对嵌有H⁺-ATP酶的脂酶体不同层次脂质流动性的影响。 （1）顺磁标记探剂5-、12-、16-氮氧基硬脂酸测定结果表明Mg²⁺和其它二价金属离子都能降低膜脂双分子层表层的流动性。降低流动性的顺序为Mg²⁺=Ca²⁺>Sr²⁺>Cd²⁺。较深层脂则无明显变化。 （2）荧光探剂7-、12-（9-蒽酰）硬脂酸及16-（9-蒽酰）棕榈酸的测定结果也表明Mg²⁺和其它二价金属离子降低了膜脂表层的流动性,尤以Mn²⁺、Ca²⁺降低流动性最显著,流动性降低的顺序为;Mn²⁺ Ca>Sr²⁺ Mg²⁺ Cd²⁺。除Mn²⁺、Ca²⁺还能影响膜脂深层的流动性外,其它与对照无明显差异。更多还原

【Abstract】 The fluidity at different depth in phospholipid bilayer of the H+-ATPase containing-proteoliposmes reconstituted in the presence and absence of bivalent cations have been measured and compared by using spin labels or fluorescent probes.1. Results of ESR experiments by using 5-NS spin labels showed the Mg2+, Ca2+, Sr2+, or Cd2+ decreased the fluidity near the polar faces in the phospholipid bilayer of the H+-ATPase containing-proteoliposomes. The effectiveness of these bivalent cations in decreasing order was Mg2-+≈Ca2+>Sr2+>Cd2+. But the fluidity of Me2+-’free’and Me2+-containing proteoliposome preparations was not obviously different in the deeper regions of the phospholipid bilayer, monitored by using spin labels 12-NS and 16-NS.2, A set of n- (9-anthroyloxy) fatty acids (n = 7, 12, 16) have also been used as fluorescent probes to examine the lipid environment at different depths in phospholipid bilayer of the Me2+-’free’and Me2+-containing proteoliposomes. Results of fluorescent polarization experiments showed that the fluorescent probes 7AS, 7- (9-anthroyloxy) stearic acid rotates slower in the Me2+-containing than in the Me2+-’free’proteoliposomes. The effectiveness of tested bivalent cations decreased in the order. Mn2+###Ca2+>Sr2+≈Mg2+≈Cd2+. In the case of the fluo resent probe 12AS or 16AP [16-(9-anthroyloxy) palmitic acid], there was no obvious different between Me2+-’free’and Me2+-containing proteoliposomes, except Mn2+ or Ca2+.更多还原