title: Antioxidative properties of tripeptide libraries prepared by the combinatorial chemistry.
abstract: Two series of combinatorial tripeptide libraries were constructed, based on an antioxidative peptide isolated from a soybean protein hydrolysate. One was a library of 108 peptides containing either His or Tyr residues. Another was a library of 114 peptides related to Pro-His-His, which had been identified as an active core of the antioxidative peptide. The antioxidative properties of these libraries were examined by several methods, such as the antioxidative activity against the peroxidation of linoleic acid, the reducing activity, the radical scavenging activity, and the peroxynitrite scavenging activity. Two Tyr-containg tripeptides showed higher activities than those of two His-containing tripeptides in the peroxidation of linoleic acid. Tyr-His-Tyr showed a strong synergistic effects with phenolic antioxidants. However, the tripeptide had only marginal reducing activity and a moderate peroxynitrite scavenging activity. Cysteine-containing tripeptides showed the strong peroxynitrite scavenging activity. Change of either the N-terminus or C-terminus of Pro-His-His to other amino acid residues did not significantly alter their antioxidative activity. Tripeptides containing Trp or Tyr residues at the C-terminus had strong radical scavenging activities, but very weak peroxynitrite scavenging activity. The present results allow us to understand why protein digests have such a variety of antioxidative properties.
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Saito
authors.forename: Dong-Hao
authors.initials: DH
authors.lastname: Jin
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Koji
authors.initials: K
authors.lastname: Muramoto
authors.forename: Eiko
authors.initials: E
authors.lastname: Hatakeyama
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yasuhara
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Nokihara
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D019151:Peptide Library; D011492:Protein Hydrolysates / Q000032:analysis / Q000494:pharmacology*; D030262:Soybean Proteins
chemical_list: D000975:Antioxidants; D019151:Peptide Library; D011492:Protein Hydrolysates; D030262:Soybean Proteins