大豆蛋白亚基组成的不同直接影响大豆蛋白的加工特性与营养特性。本研究利用SDS-PAGE电泳分析大豆蛋白质组成并提出了便捷的样品预处理方法。对1 624个中国大豆栽培品种的分析结果表明，构成大豆蛋白的主要亚基均有一定变异，同时，结合Western Blot分析，首次在中国大豆栽培品种中发现了β-伴大豆球蛋白的β-亚基缺失的大豆品种，为大豆蛋白质的品质改良育种和加工理论研究提供了重要的材料。
Soybean is a good food resource of plant protein. Processing characteristics of soybean have been found to have a close relationship with the subunit composition of soy protein. Mutant soybean lines lacking α, α′ subunits or with lower ratio of β subunit were induced by γ-ray irradiation. China has a wide natural soybean germplasm variation in terms of cultivars with different properties including anti-disease, high oil content, high protein content, respectively. However, systematic evaluation of this occurrence on protein composition had been rarely investigated. The aim of this work was to identify the soybean germplasm variation with certain subunits absence therefore enable a deeper insight of its relationship with functional properties of soy protein.
Based on Laemmli’s(1970) method, the subunit composition of soy protein extracted from 1 624 Chinese soybean cultivars was analyzed by SDS-PAGE electrophoresis, and a simplified sample pre-treatment method was proposed(Fig.1). This qualitative analysis revealed that there were many native aberrant varieties having a lower proportion of or lacking A3, A5, γ, β-subunits in the 1624 soybean cultivars (Table 1). The SDS-PAGE patterns of some distinct soybean cultivars lacking certain subunit were shown(Fig.2-a, Fig.2-b). In addition, the result of Western Blot analysis proved the finding of a unique soybean cultivar lacking the β subunit in β-conglycinin(Fig.3, Fig.4), which was first reported among Chinese soybean cultivars. Thus it provides an essential material for further breeding experiments to improve the functional quality of soy protein.
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