"Study on physical properties of inositol phospholipid in cellular signal transduction"

磷脂酸在细胞功能中起着重要的作用，例如，细胞的增殖、质膜上的信号转导和钙离子的动员。用差示扫描量热法和X射线衍射法研究了磷脂酸与聚L赖氨酸和钙离子的相互作用。在磷脂酸/聚L-赖氨酸体系上的研究结果表明，聚L-赖氨酸与磷脂酸的相互作用是静电作用，不影响磷脂双层膜的堆积，且相互作用不遵循一对一的计量比。进一步分析X射线衍射数据，给出了磷脂酸/聚(L-赖氨酸)膜的可能模型。对磷脂酸/(磷脂酰胆碱和/或磷脂酰乙醇胺)/Ca~(2+)体系的量热研究揭示了由混合磷脂组成的膜的精细结构。在这些膜中，磷脂酸不是被钙离子完全分离，而是散布在膜中。本研究有助于进一步研究膜结构与功能的关系。

Phosphatidic acids play an important role in cellular function ; for example, proliferation of a cell, signal transduction on plasma membranes and mobilization of calcium ions. In the present study, interactions of phosphatidic acid with poly (L-lysine) and calcium ions were investigated by differential scanning calorimetry and X-ray diffraction technique. Results on phosphatidic acid/poly (L-lysine) system indicate that poly (L-lysine) interacts with phosphatidic acid electrostatically without affecting the chain-packing of the lipid bilayer membranes and that the interaction does not obey the one-to-one sto ichiometry. Further analysis of X-ray diffraction data gives a probable model of phosphatidic acid/poly (L-lysine) membranes. Calorimetric study on phosphatidic acid/ (phosphatidylcholine and/or phosphatidylethanolamine) /Ca2+ system elucidates a fine structure of membranes composed of the mixed phospholipids. In these membranes, phosphatidic acid is not completely segregated by Ca2+ but studded in the membranes. The present study is helpful to proceed a research of relationship between membrane structure and function.