Screening of ACE-inhibitory peptides from a random peptide-displayed phage library using ACE-coupled liposomes.
Angiotensin I converting enzyme (ACE)-inhibitory peptides were screened from a random peptide-displayed phage library using ACE-coupled liposomes. Among four kinds of inhibitory peptides selected by biopanning with two different elution strategies, a peptide (LSTLRSFCA) showed the highest inhibitory activity with an IC(50) value of 3microM. By measuring inhibitory activities of fragments of the peptide, it was found that the RSFCA region was a functional site to inhibit strongly the ACE catalytic activity, and particularly both Arg and Cys residues were essential for the strong inhibitory activity. The inhibitory activity of RRFCA was slightly increased, while that of the RSFRA, in which the Cys residue was replaced by Arg, was decreased to greater extent in comparison with the inhibitory activity of RSFCA. Taking into account the results obtained from the SPOT analysis, it was suggested that the Arg and Phe residues in RSFCA were important for a specific interaction with ACE, and the Cys residue inhibited the ACE activity. The cystein-based ACE-inhibitory peptides have not been isolated from processed food materials. These findings suggested that the biopanning method utilizing protein-coupled liposomes and random peptide libraries might have a possibility to screen new functional peptides that are not found in processed food materials.
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
Yoichi
Y
Kumada
Naoya
N
Hashimoto
Fida
F
Hasan
Masaaki
M
Terashima
Kazuhiro
K
Nakanishi
Alois
A
Jungbauer
Shigeo
S
Katoh
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification*; D000818:Animals; D001665:Binding Sites; D004353:Drug Evaluation, Preclinical; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000302:isolation & purification*; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits
D000806:Angiotensin-Converting Enzyme Inhibitors; D004800:Enzymes, Immobilized; D008081:Liposomes; D019151:Peptide Library; D010455:Peptides; D007703:Peptidyl-Dipeptidase A