title: Transport of Egg White ACE-Inhibitory Peptide, Gln-Ile-Gly-Leu-Phe, in Human Intestinal Caco-2 Cell Monolayers with Cytoprotective Effect.
abstract: The purpose of this study was to investigate the transepithelial transport and cytoprotective effect of Gln-Ile-Gly-Leu-Phe (QIGLF), an ACE-inhibitory peptide derived from egg white ovalbumin, in human intestinal Caco-2 cell monolayers. The results showed that QIGLF could be absorbed intact through Caco-2 cell monolayers with a Pappvalue of (9.11 ± 0.19) × 10-7cm/s (transport kinetic parameters: Km, 32.37 ± 12.59 mM; Vmax, 1.23 ± 0.49 μM/min cm2). The transport was not significantly decreased by sodium azide and Gly-Pro, an ATP synthesis inhibitor and a peptide transporter 1 (PepT1) substrate, respectively, suggesting that transport of QIGLF was not energy-dependent and carrier-mediated. In addition, wortmannin, a transcytosis inhibitor, had little effect on the transport, suggesting that endocytosis was not involved in the transport of QIGLF. However, the transport of QIGLF was increased significantly in the presence of cytochalasin D, a tight junction disruptor, suggesting that paracellular transport via tight junctions was the major transport mechanism for intact QIGLF across Caco-2 cell monolayers. Moreover, QIGLF was added to Caco-2 cells followed by addition of H2O2, and exhibited significant cytoprotective effect in Caco-2 cells against oxidative stress induced by H2O2.
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University , Changchun 130062, People's Republic of China.
authors.forename: Long
authors.initials: L
authors.lastname: Ding
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University , Changchun 130062, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Life Science, Jilin University , Changchun 130021, People's Republic of China.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University , Changchun 130062, People's Republic of China.
authors.forename: Liying
authors.initials: L
authors.lastname: Wang
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University , Changchun 130062, People's Republic of China.
authors.forename: Boqun
authors.initials: B
authors.lastname: Liu
authors.affiliation: Laboratory of Nutrition and Functional Food, Jilin University , Changchun 130062, People's Republic of China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Liu
keywords: ACE-inhibitory peptide; Caco-2 cells; egg white; transport