pH值和热处理对不同制剂中马铃薯蛋白结构和溶解性的影响。

Effects of pH and heat treatments on the structure and solubility of potato proteins in different preparations.

作者信息

van Koningsveld G A, Gruppen H, de Jongh H H, Wijngaards G, van Boekel M A, Walstra P, Voragen A G

机构信息

Centre for Protein Technology, TNO-WU, Wageningen, The Netherlands.

出版信息

J Agric Food Chem. 2001 Oct;49(10):4889-97. doi: 10.1021/jf010340j.

DOI:10.1021/jf010340j

PMID:11600040

Abstract

The soluble potato proteins are mainly composed of patatin and protease inhibitors. Using DSC and both far-UV and near-UV CD spectroscopy, it was shown that potato proteins unfold between 55 and 75 degrees C. Increasing the ionic strength from 15 to 200 mM generally caused an increase in denaturation temperature. It was concluded that either the dimeric protein patatin unfolds in its monomeric state or its monomers are loosely associated and unfold independently. Thermal unfolding of the protease inhibitors was correlated with a decrease in protease inhibitor activities and resulted in an ionic strength dependent loss of protein solubility. Potato proteins were soluble at neutral and strongly acidic pH values. The tertiary structure of patatin was irreversibly altered by precipitation at pH 5. At mildly acidic pH the overall potato protein solubility was dependent on ionic strength and the presence of unfolded patatin.

摘要

可溶性马铃薯蛋白主要由马铃薯块茎蛋白和蛋白酶抑制剂组成。通过差示扫描量热法（DSC）以及远紫外和近紫外圆二色光谱表明，马铃薯蛋白在55至75摄氏度之间展开。将离子强度从15 mM增加到200 mM通常会导致变性温度升高。得出的结论是，要么二聚体蛋白马铃薯块茎蛋白以单体状态展开，要么其单体松散结合并独立展开。蛋白酶抑制剂的热展开与蛋白酶抑制剂活性的降低相关，并导致蛋白质溶解度的离子强度依赖性损失。马铃薯蛋白在中性和强酸性pH值下可溶。马铃薯块茎蛋白的三级结构在pH 5时通过沉淀不可逆地改变。在轻度酸性pH下，马铃薯蛋白的总体溶解度取决于离子强度和未折叠的马铃薯块茎蛋白的存在。