Piéroni G, Gargouri Y, Sarda L, Verger R
Centre de Biochimie et de Biologie Moléculaire, CNRS, Marseille, France.
Adv Colloid Interface Sci. 1990 Sep;32(4):341-78. doi: 10.1016/0001-8686(90)80023-s.
Among the proteins, lipolytic enzymes provide a valuable model for studying protein-lipid interactions. Lipases having a catalytic action which is strictly dependent upon the presence of a lipid interface were used in the present study in order to gain better insight into protein-lipid interactions. Most of the data presented here were obtained using the monolayer technique, by recording (either independently or simultaneously) the lipolytic activity, the amount of protein adsorbed to the lipid monolayer, and the surface pressure variations following protein adsorption. Several non-enzymatic proteins were used as controls in order to determine how lipase behaviour differs from that of other proteins. At all initial surface pressures tested, with zwitterionic monolayers, a good correlation was observed between the amount of lipase bound to the monolayer and the surface pressure increase, in agreement with previous studies. Conversely, with neutral lipid monolayers the amount of lipase bound to the monolayer was not found to be surface pressure dependent. This latter behaviour observed with lipases on neutral films is not specific to lipases, since it was also observed with bovine serum albumin and beta-lactoglobulin A. Lipase activity in the presence of various proteins was investigated with monomolecular films of glycerol didecanoate, either at constant surface area or at constant surface pressure. Depending upon the nature of the lipase and the protein, inhibition of lipase activity was either observed or not. Inhibition was correlated with a decrease in lipase surface concentration. The ability of the various proteins to inhibit lipolysis is: (i) a function of their excess versus lipase in the bulk phase, and: (ii) correlated with their penetration capacity (i.e., the initial rate of surface pressure increase of a glycerol didecanoate monolayer having an initial surface pressure of 20 dyn/cm, after the injection-of the protein). Since lipase inhibition was observed with low surface densities of inhibitory proteins, a long-range effect is probably involved in the mechanism of interfacial lipase inhibition. The nature of the ionic charge added to the monolayer by the protein is not critical for determining lipase adsorption or desorption. It is hypothesized that the lack of lipase adsorption to, or desorption from, the lipid monolayer results from a change in the organization of the hydrocarbon moiety of the lipid.
在蛋白质中，脂解酶为研究蛋白质 - 脂质相互作用提供了一个有价值的模型。本研究使用了催化作用严格依赖脂质界面存在的脂肪酶，以便更好地洞察蛋白质 - 脂质相互作用。这里呈现的大部分数据是使用单层技术获得的，通过（独立或同时）记录脂解活性、吸附到脂质单层的蛋白质量以及蛋白质吸附后表面压力的变化。使用了几种非酶蛋白作为对照，以确定脂肪酶的行为与其他蛋白质的行为有何不同。在所有测试的初始表面压力下，对于两性离子单层，观察到结合到单层的脂肪酶量与表面压力增加之间有良好的相关性，这与先前的研究一致。相反，对于中性脂质单层，未发现结合到单层的脂肪酶量与表面压力有关。在中性膜上脂肪酶观察到的后一种行为并非脂肪酶所特有，因为在牛血清白蛋白和β - 乳球蛋白A中也观察到了这种情况。在恒定表面积或恒定表面压力下，用甘油二癸酸酯的单分子膜研究了各种蛋白质存在时的脂肪酶活性。根据脂肪酶和蛋白质的性质，观察到或未观察到脂肪酶活性的抑制。抑制与脂肪酶表面浓度的降低相关。各种蛋白质抑制脂解的能力：（i）是它们在本体相中相对于脂肪酶过量的函数，并且：（ii）与它们的渗透能力相关（即，在注入蛋白质后，初始表面压力为20达因/厘米的甘油二癸酸酯单层表面压力增加的初始速率）。由于在抑制性蛋白质的低表面密度下观察到脂肪酶抑制，界面脂肪酶抑制机制可能涉及长程效应。蛋白质添加到单层中的离子电荷性质对于确定脂肪酶的吸附或解吸并不关键。据推测，脂肪酶在脂质单层上缺乏吸附或解吸是由于脂质烃部分组织的变化。
