Role of the palmitoylation of surfactant-associated protein C in surfactant film formation and stability
Role of the palmitoylation of surfactant-associated protein C in surfactant film formation and stability
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DOI：
10.1152/ajplung.1996.271.4.l572
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发表时间：
1996-10-01
影响因子：
4.9
通讯作者：
Schurch, S
中科院分区：
文献类型：
--
作者：
Qanbar, R;Cheng, S;Schurch, S
本文研究了肺表面活性物质相关蛋白C（SP-C）棕榈酰化对二棕榈酰磷脂酰胆碱和磷脂酰甘油磷脂混合物表面活性的影响。在中性和酸性pH下，使用捕获气泡表面活性计检查用棕榈酰化或脱棕榈酰化牛SP-C重构的磷脂。在低pH值下，即使不含蛋白质的样品也能获得有效的脂质吸附和压缩后接近零的表面张力。在生理pH值下，只有含SP-C的样品才能获得这样的性质。通过先前的SP-C脱棕榈酰化降低脂质吸附。具有棕榈酰化SP-C的气泡具有更高的机械稳定性，并且需要较少的压缩以达到低表面张力。亚相耗竭实验表明，动态循环的表面层含有棕榈酰SP-C保持其表面活性后亚相脂质耗竭。相反，在包括脱棕榈酰化的SP-C或SP-B的情况下，表面活性迅速丧失。我们的研究结果表明，虽然SP-C棕榈酰化的能力，以提高脂质吸附和表面张力降低的影响不大，它大大提高了脂质respreading和膜的稳定性，因此是重要的表面活性剂功能。
The effect of palmitoylation of pulmonary surfactant-associated protein C (SP-C) on the surface activity of phospholipid mixtures of dipalmitoylphosphatidylcholine and phosphatidylglycerol was studied. Phospholipids reconstituted with palmitoylated or depalmitoylated bovine SP-C were examined at neutral and acidic pH using a captive bubble surfactometer. At low pH, effective lipid adsorption and near zero surface tensions upon compression were obtained even with protein-free samples, At physiological pH, only SP-C-containing samples achieved such properties. Lipid adsorption was decreased by prior SP-C depalmitoylation. Bubbles with palmitoylated SP-C were more mechanically stable and required less compression to reach low surface tensions. Subphase depletion experiments showed that dynamically cycled surface layers containing palmitoylated SP-C maintained their surface activity after subphase lipid depletion. In contrast, surface activity was rapidly lost where depalmitoylated SP-C or SP-B tvas included. Our results indicate that although SP-C palmitoylation has little effect on its ability to enhance lipid adsorption and surface tension reduction, it greatly enhances lipid respreading and film stability and is therefore important for surfactant function.