Pal Prabir, Kamilya Tapanendu, Mahato Mrityunjoy, Talapatra G B
Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
Colloids Surf B Biointerfaces. 2009 Oct 1;73(1):122-31. doi: 10.1016/j.colsurfb.2009.05.008. Epub 2009 May 18.
We report herein the formation of pepsin monomolecular layer by the Langmuir-Blodgett film deposition technique. An effort was made to find an optimal subphase by adjusting the concentration of salt (KCl) and pH by monitoring the growth kinetics of pepsin for the formation of Langmuir monolayer by using as little as possible pepsin molecules to build up ultra thin film and to measure the extent of denaturation. Significant changes of area/molecule, compressibility, rigidity and unfolding of pepsin are observed at optimized subphase than pure water subphase. Observations at optimal subphase are explained in context of the modified DLVO theory and the site dissociation model. FTIR analysis of amide band together with the observed surface morphology of pepsin film in FE-SEM images indicate that at optimal subphase the pepsin molecules modify their structures by incrementing the beta-structure, resulting into larger unfolding and inter-molecular aggregates.
我们在此报告通过朗缪尔-布洛杰特（Langmuir-Blodgett）膜沉积技术形成胃蛋白酶单分子层的情况。通过监测胃蛋白酶的生长动力学来调整盐（KCl）浓度和pH值，以寻找最佳亚相，从而尽可能少地使用胃蛋白酶分子来构建超薄膜并测量变性程度，进而形成朗缪尔单分子层。与纯水亚相相比，在优化的亚相中观察到胃蛋白酶的面积/分子、压缩性、刚性和展开情况有显著变化。在修正的DLVO理论和位点解离模型的背景下解释了在最佳亚相下的观察结果。酰胺带的傅里叶变换红外光谱（FTIR）分析以及场发射扫描电子显微镜（FE-SEM）图像中观察到的胃蛋白酶膜表面形态表明，在最佳亚相下，胃蛋白酶分子通过增加β-结构来改变其结构，从而导致更大程度的展开和分子间聚集。
