Ippoushi Katsunari, Wakagi Manabu, Hashimoto Naoto, Takano-Ishikawa Yuko
Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
Food Research Institute, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
Food Res Int. 2019 Feb;116:1223-1228. doi: 10.1016/j.foodres.2018.10.009. Epub 2018 Oct 4.
β-Conglycinin, a major protein in soybeans, shows improvement effect of lipid metabolism. Moreover, this protein influences the processing properties of soybeans. β-Conglycinin is a hetero-trimer constituted by α, α', and β subunits. In this work, a method for the selective quantification of these subunits was developed by means of protein absolute quantification (AQUA) technology using liquid chromatography/tandem mass spectrometry with the stable isotope-labelled internal standard peptides LQSGDALR[C,N], NILEASYDTK[C,N], and NPIYSNNFGK[C,N]. This method exhibited linear relationships (r > 0.99) in the concentration range of 1.2-300 fmol/μL for LQSGDALR[C,N] and NILEASYDTK[C,N], and of 4.7-300 fmol/μL for NPIYSNNFGK[C,N]. As a result, the content of these subunits in β-conglycinin-rich and both α and α' subunit-deficient soybean cultivars was successfully determined. This quantitative assay is promising for the evaluation of the food functionality and processing properties of soybeans.
β-伴大豆球蛋白是大豆中的一种主要蛋白质，具有改善脂质代谢的作用。此外，这种蛋白质还会影响大豆的加工特性。β-伴大豆球蛋白是由α、α'和β亚基组成的异源三聚体。在本研究中，利用液相色谱/串联质谱联用技术，借助蛋白质绝对定量（AQUA）技术和稳定同位素标记的内标肽LQSGDALR[C,N]、NILEASYDTK[C,N]以及NPIYSNNFGK[C,N]，开发了一种选择性定量这些亚基的方法。该方法对于LQSGDALR[C,N]和NILEASYDTK[C,N]在1.2 - 300 fmol/μL的浓度范围内呈现线性关系（r > 0.99），对于NPIYSNNFGK[C,N]在4.7 - 300 fmol/μL的浓度范围内呈现线性关系。结果成功测定了富含β-伴大豆球蛋白以及缺乏α和α'亚基的大豆品种中这些亚基的含量。这种定量分析方法在评估大豆的食品功能和加工特性方面具有广阔前景。
