Homma R, Kouyama T, Yamada M, Niimura Y, Krivosheev A V, Hara T, Kawato S
Department of Biophysics and Life Science, Graduate School of Arts and Sciences, University of Tokyo at Komaba, Japan.
J Pharm Biomed Anal. 1997 Jun;15(9-10):1215-22. doi: 10.1016/s0731-7085(96)01980-2.
The effects of chlorpromazine on the mobility of cytochrome P-450 and the fluidity of lipid membranes have been investigated in bovine adrenocortical submitochondrial particles (SMP). Rotational diffusion of the cytochrome was measured by observing the decay of absorption anisotropy, ra(t), after photolysis of the heme.CO complex by a vertically polarized laser flash. Analysis of ra(t) was based on a 'rotation-about-membrane-normal' model. The anisotropy decayed within 2 ms to a time independent value r3. The presence of chlorpromazine decreased the mobile population of cytochrome P-450 from 28 to 23%. The rotational relaxation time phi a of the mobile population (approximately 1100 microseconds) was, however, not significantly changed by chlorpromazine. The lipid fluidity was examined by observing time-resolved fluorescence anisotropy, rf(t), of 1,6-diphenyl 1,3,5-hexatriene (DPH). The anisotropy rf(t) decayed within 70 ns to a time independent value r infinity. The motion of DPH was analyzed based on a 'wobbling-in-cone' model. The presence of chlorpromazine decreased the cone angle from 42 degrees to 39 degrees, while the rotational relaxation time phi f (approximately 2 ns) was not significantly changed by the presence of chlorpromazine. These results demonstrate that chlorpromazine decreased the mobility of not only lipids but also membrane proteins.
已在牛肾上腺皮质亚线粒体颗粒（SMP）中研究了氯丙嗪对细胞色素P - 450流动性和脂质膜流动性的影响。通过观察血红素 - CO复合物经垂直偏振激光闪光光解后吸收各向异性ra(t)的衰减来测量细胞色素的旋转扩散。ra(t)的分析基于“绕膜法线旋转”模型。各向异性在2毫秒内衰减至与时间无关的值r3。氯丙嗪的存在使细胞色素P - 450的可移动群体从28%降至23%。然而，可移动群体的旋转弛豫时间phia（约1100微秒）并未因氯丙嗪而发生显著变化。通过观察1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）的时间分辨荧光各向异性rf(t)来检测脂质流动性。各向异性rf(t)在70纳秒内衰减至与时间无关的值r∞。基于“圆锥内摆动”模型分析DPH的运动。氯丙嗪的存在使圆锥角从42度降至39度，而旋转弛豫时间phif（约2纳秒）并未因氯丙嗪的存在而发生显著变化。这些结果表明，氯丙嗪不仅降低了脂质的流动性，还降低了膜蛋白的流动性。
