本文采用Osborne分级法制备竹豆清蛋白，并采用氨基酸自动分析仪、还原聚丙烯酰胺凝胶电泳（SDS-PAGE）、示差扫描量热仪（DSC）和傅里叶红外光谱（FT-IR）分别对其氨基酸组成、亚基分子量分布、热学性质及二级结构作初步研究。结果表明竹豆清蛋白含有全面且丰富的必需氨基酸，属于一种优质植物蛋白。SDS-PAGE电泳表明竹豆清蛋白含有9个亚基条带，最主要的亚基分子量分布在49.6 ku和27.6 ku。热分析显示竹豆清蛋白变性温度（Td）在pH=7.0时最高，达100.6 ℃；变性焓（ΔH）在pH=5.0时最大，达3.40 J/g。傅里叶红外显示其二级结构分布如下：β转角最高（33.59%），其次是β折叠（31.38%），α螺旋（17.97%）和无规卷曲（17.07%）。研究表明竹豆清蛋白营养价值丰富，亚基分子量分布广，有较强的热稳定性，具有高度有序且稳定的结构，这为后续研究竹豆清蛋白的功能特性以及应用提供了理论依据。

The bamboo bean albumin was prepared by Osborne procedure in this study, and its amino acid composition, subunit molecular weight, thermal properties and the secondary structure were preliminarily studied using automatic amino acid analyzer, reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR), respectively. The results showed that bamboo bean albumin had abundant and comprehensive essential amino acids, belonging to a kind of high quality plant protein. Bamboo bean albumin contained nine subunits confirmed by SDS-PAGE, and the main subunits were distributed in 49.6 ku and 27.6 ku. Thermal analysis showed that the bamboo bean albumin had the highest denaturation temperature (Td) of 100.6℃ at pH = 7.0. And it had the highest degeneration enthalpy (ΔH) of 3.40 J/g at pH = 5.0. The fourier transform infrared spectroscopy showed its secondary structure was as follows: the proportion of beta angle was the highest (33.59%), followed by beta folding (31.38%), alpha helix (17.97%) and random coil (17.07%). Studies showed that bamboo bean albumin had rich nutritional value, wide molecular weight distribution, strong thermal stability, and highly ordered and stable structure, which provided a theoretical basis for subsequent research on the functional properties and application of bamboo bean albumin.

国家高技术研究发展计划（863计划）项目（2013AA102203-03）