He Shudong, Simpson Benjamin K, Ngadi Michael O, Ma Ying
School of Food Science and Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China; Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada.
Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada.
Food Chem. 2015 Apr 15;173:397-404. doi: 10.1016/j.foodchem.2014.10.045. Epub 2014 Oct 17.
In this study, the in vitro digestibility of lectin from black turtle bean was investigated in simulated gastric fluid (SGF) and tryptic digestion, using kinetic densitometric analysis for SDS-PAGE and spectroscopic measurements. It was found that the native lectin was relatively stable in both SGF (half-life=22.71 min) and tryptic digestion (half-life ⩾90 min), the susceptibility of the protein to hydrolysis by proteases was markedly increased by preheating and also enhanced by demetallization. An unfolding state of the preheated lectin was observed by UV and fluorescence spectroscopy, although the conformational changes were found to be limited by the demetallization. This study provides evidence that metal ions may provide resistance during protease hydrolysis, and suggests both preheating and demetallization contribute to in vitro proteolytic degradation of lectin.
在本研究中，利用SDS-PAGE的动力学光密度分析和光谱测量，研究了黑龟豆凝集素在模拟胃液（SGF）和胰蛋白酶消化中的体外消化率。结果发现，天然凝集素在SGF（半衰期=22.71分钟）和胰蛋白酶消化（半衰期⩾90分钟）中都相对稳定，预热显著增加了蛋白质对蛋白酶水解的敏感性，脱金属也增强了这种敏感性。通过紫外和荧光光谱观察到预热凝集素的解折叠状态，尽管发现构象变化受到脱金属的限制。本研究提供了证据表明金属离子可能在蛋白酶水解过程中提供抗性，并表明预热和脱金属都有助于凝集素的体外蛋白水解降解。
