Functional properties and conformational changes of food proteins - Roles of molten globule state

食品蛋白质的功能性质与其构象状态密切相关。在本研究项目中，我们以卵清蛋白(卵清蛋白和卵转铁蛋白)和血清白蛋白为模型蛋白，研究了食物蛋白质构象变化的机制。1.在2.4A分辨率下测定了两种铁结合型转铁蛋白的X射线晶体结构。通过与二硫苏糖醇的孵育，得到了二硫还原态的转铁蛋白和血清白蛋白，并用圆二色谱和本征色氨酸荧光光谱分析了它们的构象特征。这些蛋白质形态呈熔融球状构象。3.卵转铁蛋白和血清白蛋白通过二硫键还原形成不透明凝胶。因此，熔融的球状状态作为这些蛋白质的关键构象状态参与了凝胶过程。

The functional properties of food proteins are closely related to their conformational state. In this research project, we investigated the mechanisms for the conformational changes in food proteins, using egg white proteins (ovalbumin and ovotransferrin) and serum albumin as model proteins.1.The X-ray crystallographic structure of both the iron-bound form of ovotransferrin was determined at 2.4 A resolution. It was found that the conformation of the protein is induced into a much more compact form by the iron-bindings.2.The disulfide-reduced forms of ovotransferrin and serum albumin were produced by incubation with dithiothreitol and their conformational characteristics were analyzed by the circular dichroism and intrinsic tryptophan fluorescence spectra. These protein forms were found to assume the molten globule like conformation.3.Both ovotransferrin and serum albumin were found to form opaque gels by their disulfide reduction. It was therefore concluded that the molten globule state is involved in the gelation process as crucial conformational states of these proteins.