Katayama Shigeru, Ishikawa Shin-Ichi, Fan Ming Z, Mine Yoshinori
Departments of Food Science and Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada.
J Agric Food Chem. 2007 Apr 18;55(8):2829-35. doi: 10.1021/jf0628936. Epub 2007 Mar 23.
Previously, we have found phosphopeptides (PPPs) from hen egg yolk phosvitin possess a potent antioxidative activity against oxidative stress in human intestinal epithelial cells, Caco-2. However, their biological activity at the cellular level has not yet fully understood. The objective of this study is to evaluate the regulation of glutathione (GSH) biosynthesis-associated and antioxidant enzymes against oxidative stress in Caco-2 cells using an in vitro model. Treatment of 1 mM H2O2-induced Caco-2 cells with PPPs increased cellular GSH levels, concomitant with a significant increase in gamma-glutamylcysteine synthetase (gamma-GCS) activity and the expression of gamma-GCS heavy subunit mRNA. Furthermore, intracellular glutathione reductase, glutathione S-transferase, and catalase activities were elevated by PPPs. In addition, PPPs with high content of phosphorus showed higher induction of these enzyme activities than PPPs without phosphorus. These data indicate that oligophosphopeptides from hen egg yolk phosvitin can up-regulate cellular GSH biosynthesis-associated enzymes activity and antioxidative activities, which play key roles against tissue oxidative stress in the human intestinal epithelial cells.
此前，我们已发现来自鸡蛋黄卵黄高磷蛋白的磷酸肽（PPPs）对人肠上皮细胞Caco-2中的氧化应激具有强大的抗氧化活性。然而，它们在细胞水平上的生物学活性尚未完全明确。本研究的目的是使用体外模型评估谷胱甘肽（GSH）生物合成相关酶和抗氧化酶对Caco-2细胞氧化应激的调节作用。用PPPs处理1 mM H2O2诱导的Caco-2细胞可提高细胞内GSH水平，同时γ-谷氨酰半胱氨酸合成酶（γ-GCS）活性及γ-GCS重亚基mRNA的表达显著增加。此外，PPPs可提高细胞内谷胱甘肽还原酶、谷胱甘肽S-转移酶和过氧化氢酶的活性。此外，磷含量高的PPPs比无磷的PPPs对这些酶活性的诱导作用更强。这些数据表明，来自鸡蛋黄卵黄高磷蛋白的寡磷酸肽可上调细胞内GSH生物合成相关酶的活性和抗氧化活性，这对人肠上皮细胞中的组织氧化应激起着关键作用。
