Diffusion and partitioning of a pesticide, lindane, into phosphatidylcholine bilayers. A new fluorescence quenching method to study chlorinated hydrocarbon-membrane interactions.
Diffusion and partitioning of a pesticide, lindane, into phosphatidylcholine bilayers. A new fluorescence quenching method to study chlorinated hydrocarbon-membrane interactions.
复制标题
农药林丹扩散并分配到磷脂酰胆碱双层中。
DOI：
10.1016/0005-2736(77)90045-1
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
G. Omann
中科院分区：
文献类型：
--
作者：
J. Lakowicz;D. Hogen;G. Omann
氯代烃类，如杀虫剂林丹（γ-六氯环己烷），会淬灭咔唑的荧光。观察到的淬火是扩散碰撞时发生的分子接触的结果。由于猝灭的量取决于咔唑和农药之间的碰撞频率，因此这种现象提供了对linectin的扩散速率及其局部浓度的测量。通过将脂质与新合成的磷脂β-（11-（9-咔唑）-十一烷酰基）-l-α-磷脂酰胆碱共超声处理，将咔唑荧光团定位在磷脂酰胆碱双层内。在二肉豆蔻酰-l-α-磷脂酰胆碱囊泡中使用这种探针，以及上述的淬灭现象，我们确定在37° C时双层内的线性扩散速率为5.7· 10− 7 cm 2/s。在各种浓度的二肉豆蔻酰磷脂酰胆碱的表观猝灭常数的测量得到的脂-水分配系数为9500，这是在协议的8980通过我们的平衡透析实验获得的值。当农药与脂质的摩尔比约为1.5时，二肉豆蔻酰-l-α-磷脂酰胆碱的囊泡被林丹饱和。0.28.这些结果证明了利用咔唑荧光猝灭来研究农药在生物膜内的运输和分配的可能性。这种能力应证明在研究氯代烃与细胞膜的相互作用中是有用的。
Chlorinated hydrocarbons, such as the pesticide lindane (γ-hexachlorocyclohexane), quench the fluorescence of carbazole. The observed quenching is a result of the molecular contacts which occur upon diffusional collisions. Because the amount of quenching depends upon the collisional frequency between carbazole and pesticide, this phenomenon provides a measure of both the diffusional rate of lindane and its local concentration. The carbazole fluorophore is localized within phosphatidylcholine bilayers by cosonicating the lipid with a newly synthesized phospholipid, β-(11-(9-carbazole)-undecanoyl)-l-α-phosphatidylcholine. Using this probe in dimyristoyl-l-α-phosphatidylcholine vesicles, and the above mentioned quenching phenomena, we determined the lindane diffusion rate within the bilayer to be 5.7· 10− 7 cm 2/s at 37° C. Measurement of the apparent quenching constant at various dimyristoyl phosphatidylcholine concentrations yielded a lipid-water partition coefficient for lindane of 9500, which is in agreement with the value of 8980 obtained by our equilibrium dialysis experiments. Vesicles of dimyristoyl-l-α-phosphatidylcholine become saturated with lindane at a pesticide to lipid molar ratio of approx. 0.28. These results demonstrate the possibility of using the quenching of carbazole fluorescence to investigate the transport and partitioning of pesticides within biological membranes. This ability should prove useful in studies of the interactions of chlorinated hydrocarbons with cell membranes.