Supernovich C, Crain R, Rosenberg P
Section of Pharmacology and Toxicology, School of Pharmacy, University of Connecticut, Storrs 06269.
J Neurochem. 1991 Aug;57(2):575-84. doi: 10.1111/j.1471-4159.1991.tb03788.x.
Phosphatidylcholine asymmetry in the inner and outer leaflets of the plasma membrane bilayer of the innervated and noninnervated surfaces of the electroplax cell was determined, using a phosphatidylcholine exchange protein. The exchange protein from bovine liver catalyzed the exchange of phosphatidylcholine from small unilamellar vesicles to the outer monolayer of the plasma membrane bilayer. The exchange protein did not penetrate to the inner monolayer of the plasma membrane, did not modify the permeability of the electroplax, and did not alter the phospholipid or cholesterol content of the electroplax. In the innervated plasma membrane, 42% of the phosphatidylcholine is in the outer leaflet, 33% is in the inner leaflet, and 25% is inaccessible to the exchange protein. Corresponding values for the noninnervated plasma membrane are 56, 26, and 18%, respectively. These results are similar to phosphatidylcholine asymmetry in other biological membranes. This unique cell can be used as a model to test the effects on phospholipid asymmetry of compounds that act on the membrane.
利用磷脂酰胆碱交换蛋白，测定了电鳗细胞受神经支配和未受神经支配表面质膜双层内外小叶中的磷脂酰胆碱不对称性。来自牛肝的交换蛋白催化了磷脂酰胆碱从小单层囊泡向质膜双层外单层的交换。该交换蛋白不会穿透到质膜的内单层，不会改变电鳗的通透性，也不会改变电鳗的磷脂或胆固醇含量。在受神经支配的质膜中，42%的磷脂酰胆碱在外小叶，33%在内小叶，25%无法被交换蛋白接近。未受神经支配质膜的相应值分别为56%、26%和18%。这些结果与其他生物膜中的磷脂酰胆碱不对称性相似。这种独特的细胞可作为模型，用于测试作用于膜的化合物对磷脂不对称性的影响。
