Transport of Egg White ACE-Inhibitory Peptide, Gln-Ile-Gly-Leu-Phe, in Human Intestinal Caco-2 Cell Monolayers with Cytoprotective Effect.

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 Papp value of (9.11 ± 0.19) × 10–7 cm/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 ...