In the Langmuir monolayer technique, a single layer of molecules is formed on a water subphase. This approach was used to mimic the antitumoricidal lipid-protein complex of oleic acid and bovine α-lactalbumin called the BAMLET complex. Our previous studies have shown that at the interface, the BAMLET complex is stabilized by the hydrophobic forces supported by the hydrogen bonds. This study provides an insight into the influence of calcium ions and the experimental conditions (temperature and subphase pH) on the stability of the complex at the interface. The Langmuir technique was expanded using a dosing pump to exchange the subphase and deliver additional substances to the system. We investigated the interactions between oleic acid monolayer and α-lactalbumin in the presence of Ca2+ in the bulk and the effect of varied experimental conditions on the complex stability. The role of calcium ions in this system is important because (in addition to low pH and relatively high temperature) it affects the conformational changes within the protein molecule and facilitates the transition of α-lactalbumin into the molten globule state. A partially unfolded state is required to form the BAMLET complex. We found that the mixed monolayer spread at the interface is stable despite drastic changes in the process conditions and remains stable even after the subphase exchange. This study of molecular interactions explored by the Langmuir technique with peristaltic pump enabled to understand the role of Ca2+ in BAMLET complex formation.

中文翻译：

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动态变化条件下朗格缪尔单层膜中的脂蛋白相互作用。

在Langmuir单层技术中，单分子层形成在水子相上。该方法用于模拟油酸和牛α-乳白蛋白的抗肿瘤脂质-蛋白质复合物，称为BAMLET复合物。我们以前的研究表明，在界面处，BAMLET配合物通过氢键支持的疏水力而稳定。这项研究提供了对钙离子和实验条件（温度和亚相pH）对界面处复合物稳定性的影响的见解。使用计量泵扩展了Langmuir技术，以交换子相并将其他物质输送到系统中。我们调查了在整体存在Ca2 +的情况下，油酸单层与α-乳清蛋白之间的相互作用，以及各种实验条件对复合物稳定性的影响。钙离子在该系统中的作用很重要，因为（除了低pH和相对较高的温度外）钙离子还影响蛋白质分子内的构象变化，并促进α-乳清蛋白转变为熔融小球状。需要部分展开的状态才能形成BAMLET复合体。我们发现，尽管工艺条件发生了巨大变化，混合单层在界面处的扩散仍是稳定的，甚至在亚相交换后也保持稳定。Langmuir技术与蠕动泵研究的分子相互作用的这项研究能够了解Ca2 +在BAMLET复合物形成中的作用。