Sengupta T, Damodaran S
Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin, 53706
J Colloid Interface Sci. 1998 Oct 15;206(2):407-415. doi: 10.1006/jcis.1998.5707.
A new methodology has been developed for studying the adsorption behavior of proteins at oil-water interfaces. This technique employs the radiotracer method for monitoring adsorption of 14C-labeled proteins at the oil-water interface. The uniqueness of the new method lies in the formation of a 1000 Å thick triglyceride oil film on the water surface. beta-casein was used to generate a standard curve for relating interfacial radioactivity (µCi/m2) to cpm at the oil-water interface. Adsorption isotherm of beta-casein was determined in the bulk protein concentration range 1.5 x 10(-5)-3.8 x 10(-3)% by weight of solution. The saturated monolayer coverage was found to be about 7.3 mg/m2. This value was quite different from other values reported in the literature. Adsorption studies with another protein, lysozyme, at the oil-water interface also revealed a high surface concentration of 3.0 mg/m2. The most significant difference between the adsorption of beta-casein at the oil-water and air-water interfaces was the lack of an induction period for the development of interfacial pressure in the former. This difference may be attributed to the attractive dispersion interaction between protein molecules and the oil phase. Copyright 1998 Academic Press.
已开发出一种新方法用于研究蛋白质在油水界面的吸附行为。该技术采用放射性示踪法监测14C标记蛋白质在油水界面的吸附情况。新方法的独特之处在于在水面上形成了一层1000 Å厚的甘油三酯油膜。使用β-酪蛋白生成标准曲线，以关联界面放射性（μCi/m2）与油水界面处的每分钟计数（cpm）。在溶液重量浓度范围为1.5×10(-5)-3.8×10(-3)%的情况下测定了β-酪蛋白的吸附等温线。发现饱和单分子层覆盖率约为7.3 mg/m2。该值与文献报道的其他值有很大不同。对另一种蛋白质溶菌酶在油水界面的吸附研究也显示出高表面浓度为3.0 mg/m2。β-酪蛋白在油水界面和空气-水界面吸附之间最显著的差异在于前者界面压力发展缺乏诱导期。这种差异可能归因于蛋白质分子与油相之间有吸引力的分散相互作用。版权所有1998年学术出版社。
