Biotechnological studies on plant food proteins

最近动物性食物摄入量的增加是高张、脑部疾病等增多的原因之一。本研究的目的是通过生物技术手段，创造出质地和营养价值与动物蛋白相当的优质植物蛋白。从结构、功能性质和分子生物学的角度对各种植物食品中的蛋白质进行了研究。我们发现大豆中的主要贮藏蛋白之一的大豆球蛋白在还原或变性还原条件下具有自酰化能力，并利用这种能力产生了酰化的大豆球蛋白。麦谷蛋白的链间和链内二硫键的位置是决定小麦面粉烘焙品质的主要成分。结果1.测定了大米过敏蛋白的氨基酸序列。阐述了磷脂对面团特性的影响，通过对大豆蛋白凝胶质构特性的研究，提出了从理论上控制大豆蛋白凝胶质构的可能性。建立了不含有害物质的油菜籽蛋白的制备方法。建立了大豆球蛋白基因在大肠杆菌和酿酒酵母中的表达系统，为大豆球蛋白的蛋白质工程奠定了基础。提出了利用醇溶蛋白和谷蛋白的信号序列改变水稻蛋白体性质的可能性。测定了甘薯孢子胺和蚕豆过氧化氢酶基因的结构。提出了Ri质粒在植物转化中的可利用性，为植物食品蛋白的生物技术修饰奠定了基础。

Recent increase of animal food intake is one of the reasons why hypertonia, cerebral disease and so on are increasing. The purpose of this research is to create high quality plant proteins with texture and nutritional value comparable to those of animal proteins by means of biotechnological methods. Proteins of various plant foods were investigated from the view points of structure, functional properties and molecular biology.1. We discovered that glycinin, one of the predominant storage proteins of soybean, has an ability of autoacylation under the reduced or denatured-reduced conditions, and created acylated-glycinin using this ability. The position of interchain and intrachain disulfide bonds of glutenin, which is a main component to determine the bread making quality of wheat flour. The amino acid sequences of rice allergenic protein was determined.2. The effects of phospholipids on the characteristics of wheat dough was elucidated The possibility to control theoretically the texture of soy protein gels was proposed from the study on the texture profile of them. The method to prepare rape seed proteins which contain no harmful compounds was developed.3. We established the expression systems of soybean glycinin cDNA in Escherichia coli and Saccharomyces cerevisiae, which can be employed for protein engineering of glycinin. The possibility to change the properties of protein bodies of rice using signal sequences of prolamines and glutelins was proposed. The structure of genes encoding sporamines of sweet potato and catalase of caster bean were determined. The utilizability of Ri plasmid for plant transformation was proposed.We established the basis of biotechnological modifications of plant food proteins.