大豆球蛋白的红外和Raman光谱分析

Analysis of Soy Glycinin by FTIR and Raman Spectroscopy

利用Fourier变换红外光谱(FTIR)和激光Raman光谱研究大豆球蛋白的结构,并对大豆球蛋白的红外光谱和Raman光谱的特征峰进行指认,计算Raman费米共振I850/830的比值.结果表明:红外光谱和Raman光谱的酰胺Ⅰ带去卷积和曲线拟合获得二级结构,其中β-折叠结果差异较小,α-螺旋、β-转角和无规卷曲结果差异较大(p<0.05);红外光谱在1 618,1 682cm-1处的吸收峰归属于大豆球蛋白的分子间和分子内聚集,拟合峰面积百分数分别为11.1%和9.5%;包埋和外露的酪氨酸残基占酪氨酸残基总量的14%和86%.

The molecular structure of glycinin was investigated by FTIR and Raman spectroscopy. The frequency and signal intensity of IR and Raman bands were assigned. The data suggest that FTIR and Raman spectra reflect a large amount of structural information. The secondary structure of glycinin was assessed by the deconvolution amide I band and curve fitting. Quantitative analysis of secondary structure reveals that the results of the folded glycinin β-sheet had no significant difference, while the glycinin α-helix, turning angle, random coil had significant difference （p〈0.05）. The IR bands at 1 618 cm-1 and 1 682 cm-1 were considered to reflect the formation of intermolecular aggregates （11.1% ） and intramolecular aggregates （9.5% ）. The I850/830 intensity ratio of Raman tyrosine doublet suggests that the contents of the buried tyrosine residue and exposed tyrosine residue were 14% and 86% in glycinin.