Wang Aidong, Zhou Kai, Qi Xin, Zhao Guanghua
CAU & ACC Joint-Laboratory of Space Food College of Food Science and Nutritional Engineering Key Laboratory of Functional Dairy Ministry of Education, China Agricultural University, Beijing, 100083, China.
Plant Foods Hum Nutr. 2014 Dec;69(4):386-91. doi: 10.1007/s11130-014-0451-8.
Phytoferritin is a promising resource of non-heme iron supplementation, but it is not stable against degradation by proteases in the gastrointestinal tract. Therefore, how to improve the stability of ferritin in the presence of proteases is a challenge. Since (-)-epigallocatechin-3-gallate (EGCG) is rich in phenolic-hydroxyl groups, it could interact with ferritin through hydrogen bonds, thereby preventing protein from degradation. To confirm this idea, we focus on the interaction between EGCG and phytoferritin, and the consequence of such interaction. Results demonstrated that EGCG did interact with ferritin, and such interaction induced the change in the tertiary/quaternary structure of protein but not in its secondary structure. Furthermore, stopped-flow and dynamic light scattering (DLS) results showed that EGCG could trigger ferritin association. Consequently, such protein association markedly inhibited protein digestion by pepsin at pH 4.0 and by trypsin at pH 7.5. These findings raise the possibility to improve the stability of phytoferritin in the presence of proteases.
植物铁蛋白是一种很有前景的非血红素铁补充剂来源，但它在胃肠道中对蛋白酶降解不稳定。因此，如何在蛋白酶存在的情况下提高铁蛋白的稳定性是一项挑战。由于（-）-表没食子儿茶素-3-没食子酸酯（EGCG）富含酚羟基，它可以通过氢键与铁蛋白相互作用，从而防止蛋白质降解。为了证实这一想法，我们关注EGCG与植物铁蛋白之间的相互作用以及这种相互作用的结果。结果表明，EGCG确实与铁蛋白相互作用，并且这种相互作用导致蛋白质的三级/四级结构发生变化，但二级结构未变。此外，停流和动态光散射（DLS）结果表明，EGCG可以引发铁蛋白缔合。因此，这种蛋白质缔合在pH 4.0时显著抑制胃蛋白酶对蛋白质的消化，在pH 7.5时显著抑制胰蛋白酶对蛋白质的消化。这些发现增加了在蛋白酶存在的情况下提高植物铁蛋白稳定性的可能性。
