Identification of ACE-inhibitory peptides in salt-free soy sauce that are transportable across caco-2 cell monolayers.
In present study, we aimed to identify angiotensin I-converting enzyme (ACE)-inhibitory peptides from a salt-free soy sauce (SFS), a newly developed antihypertensive seasoning obtained by Aspergillus oryzae fermentation of soybean in the absence of salt, which can be transported through caco-2 cell monolayers. Through an Ussing transport investigation of SFS across caco-2 cell monolayers, three di-peptides, Ala-Phe, Phe-Ile and Ile-Phe, were successfully identified from the SFS as transportable inhibitory peptides. Ala-Phe and Ile-Phe, but not Phe-Ile, exhibited ACE-inhibitory activity with IC(50) values of 165.3 microM and 65.8 microM, respectively. Kinetic studies revealed that Ile-Phe (Km: 3.1 mM, P(app): 2.4 x 10(-6) cm/s) exhibited greater affinity toward the transport compared with Ala-Phe (K(m): 48.1 mM, P(app): 1.4 x 10(-6) cm/s) and Phe-Ile (K(m): 12.7 mM, P(app): 1.4 x 10(-6) cm/s).
Zhu
Xiao-Lin
XL
Division of Bioscience and Bioenvironmental Sciences, Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka, Japan.
Watanabe
Keisuke
K
Shiraishi
Koso
K
Ueki
Tatsuro
T
Noda
Yoshiharu
Y
Matsui
Toshiro
T
Matsumoto
Kiyoshi
K
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification / Q000493:pharmacokinetics*; D001692:Biological Transport; D018938:Caco-2 Cells; D002462:Cell Membrane / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007700:Kinetics; D010455:Peptides / Q000302:isolation & purification / Q000493:pharmacokinetics*; D012492:Salts; D045730:Soy Foods / Q000032:analysis*
D000806:Angiotensin-Converting Enzyme Inhibitors; D010455:Peptides; D012492:Salts