采用Osborne分级法制备芡实谷蛋白，并采用还原与非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）分别对芡实谷蛋白亚基分子量、热学性质以及二级结构作初步研究。结果表明：芡实谷蛋白主要含有6个亚基，大部分高分子量的多肽链以分子间或分子内二硫键连接；在等电点(pH=5.0)时，芡实谷蛋白的变性温度和变性焓最高；在pH=9.0溶液中变性温度和变性焓最低；随着盐浓度的升高，芡实谷蛋白的变性温度显著升高，而变性焓变化不显著，表明有更高热稳定性的结构出现；芡实谷蛋白中主要为有序结构，二级结构中β折叠所占比例最高，比例为31.16%。研究表明芡实谷蛋白含丰富的二硫键，有较强的热稳定性，结构较稳定，可为后续研究芡实谷蛋白的功能特性以及应用提供理论依据。

The Osborne procedure was used to extract glutelin from Euryale ferox, and the subunit molecular weight, thermal properties, and secondary structures of glutelin were preliminarily studied using reducing and non-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 E. ferox glutelin mainly contained six subunits, and most of the high-molecular-weight polypeptide chains were connected through intermolecular or intramolecular disulfide bonds. The highest denaturation enthalpy(ΔH) and temperature (Td) of E. ferox glutelin were observed at the isoelectric pH (pH 5.0), while the lowest ΔH and Td were observed at an alkaline pH (pH 9.0). The progressive increase in the Td of E. ferox glutelin and no pronounced changes in the ΔH were observed with increasing salt concentrations, suggesting salt-induced formation of of a conformation with higher thermal stability for E. ferox glutelin. FTIR analysis indicated that the main structure of E. ferox glutelin was ordered, and the proportion of β-sheet (31.16%) was the highest in the secondary structures. The present results indicate that E. ferox glutelin has numerous disulfide bonds, good thermal stability, and a stable structure. These results provide a theoretical basis for future studies of the functional characteristics and application of E. ferox glutelin.

国家“863”计划项目(2013AA102203-03)