Calcium modulates fatty acid dynamics in rat liver plasma membranes.
Calcium modulates fatty acid dynamics in rat liver plasma membranes.
复制标题
钙调节大鼠肝脏质膜中的脂肪酸动态。
DOI：
10.1111/j.1432-1033.1983.tb07392.x
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Soler-Argilaga,C
中科院分区：
文献类型：
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作者：
Schroeder,F;Soler-Argilaga,C
利用荧光脂肪酸分别作为饱和脂肪酸和不饱和脂肪酸的类似物，研究了游离脂肪酸在离体大鼠肝细胞膜上的结合调节。生理水平的Ca2+抑制了反式- parinarate和非顺式- parinarate的结合。添加过量EGTA后，效果被逆转。钙降低了反式- parinaric在肝质膜上的水脂分配系数Kp，同时增加了反式- parinaric的kkp。此外，Ca2+还改变了荧光寿命、量子产率以及反式- parinaric和顺式- parinaric在流体和固相中的相对分配。钙和EGTA不影响1,6 -二苯基- 1,3,5 -己三烯的结合。Ca2+对肝质膜结构的影响是增加膜的刚性，主要是固体结构域。在不含Ca2+的情况下，肝质膜中反式-对苯二甲酸酯、顺式-对苯二甲酸酯和1,6 -二苯基- 1,3,5 -己三烯在24°C时的荧光极化分别为0.295±0.008、0.253±0.007和0.284±0.005。钙（2.4 mM）使这些探针分子在肝质膜上的极化增加了8-10%。EGTA （3.4 mM）逆转或消除了极化的增加。因此，荧光脂肪酸-滨酸酯和顺式-滨酸酯可用于监测脂肪酸与分离膜的结合，评估调节脂肪酸结合的Ca2+等因素，并研究脂肪酸所在的微环境。这些数据表明，Ca2+可能是肝质膜摄取脂肪酸的重要调节剂，因此在不涉及脂溶酶或合成酶的步骤中与脂质中间代谢相互作用。
Modulation of free fatty acid binding in isolated rat liver plasma membrances was evaluated using the fluorecent fatty acidstrans‐parinaric andcis‐parinaric acid as analogues for saturated and unsaturated fatty acids, respectigvely. Binding oftrans‐parinarate but notcis‐parinarate was inhibited by physiological levels of Ca2+. The effect was revedrsed by addition of excess EGTA. Calcium decreased the aqueous to lipid partition coefficient,Kp, oftrans‐parinaric acid for liver plasma membrances while increasing theKpfortrans‐parinaric acid. In addition, Ca2+also altered the fluorescence lifetime, the quantum yield, and the relative partitioning oftrans‐parinaric andcis‐parinaric acid into fluid and solid phases. Calcium and EGTA did not affect the binding of 1, 6‐diphenyl‐1,3,5‐hexatriene. The effect of Ca2+on the liver plasma membrane structure was to increase the rigidity of the membrane, primarily the solid domain. The fluorescence polarization oftrans‐parinarate,cis‐parinarate, and 1,6‐diphenyl‐1,3,5‐hexatriene at 24°C in liver plasma membranes in the absence of Ca2+was 0.295 ± 0.008, 0.253 ± 0.007, and 0.284 ± 0.005, respectively. Calcium (2.4 mM) increased the polarization of these probe molecules in liver plasma membrances by 8–10%. EGTA (3.4 mM) reversed or abolished the increase in polarization. Thus, the fluorescent fatty acidstrans‐parinarate andcis‐parinarate may be used to monitor fatty acid binding by isolated membranes, to evaluate factors such as Ca2+which modulate fatty acid binding, and to investigate the microenvironemtn in which the fatty acids reside. The data suggest that Ca2+may be an important regulator of fatty acid uptake by the liver plasma membrane, and therby interact with intermediary metabolism of lipids at a step not involging lipolytic or synthetic enzymes.