Metal binding novel flaxseed peptides (linusorbs)

作者：Pramodkumar D. Jadhav, Yang Zuo, Youn Young Shim, Jianheng Shen, Martin J. T. Reaney, Ning Zhang, Yong Wang · 发表于：International Journal of Food Science & Technology · 年份：2018 · DOI：10.1111/ijfs.13786 · 被引用次数：8 · 研究领域：Protein Hydrolysis and Bioactive Peptides、Phytoestrogen effects and research、Probiotics and Fermented Foods

Summary Linusorbs ( LO s; a.k.a. cyclolinopeptides) are naturally occurring orbitides derived from flaxseed. These compounds consist of 8–10 amino acid residues, which are linked via an N ‐ to C‐terminal peptide bond with molecular masses of approximately 1 kD a. The LO circular structure makes them candidates for metal binding studies. Flaxseed extracts are known to suppress Pb and Cd toxicity. Hence, four metal salts surveyed include Zn( CH 3 COO ) 2 , Zn SO 4 , Pb( CH 3 COO ) 2 and Cd( NO 3 ) 2 with pure LO s 1–5 . Proton NMR spectra indicated interaction of LO s with metal salts in solution and were used to determine impacts of methionine oxidation on interactions with metal ions. The methyl group of methionine S,S ‐ dioxide of related LO s did not show the same shift in the presence of Zn( CH 3 COO ) 2 and Pb( CH 3 COO ) 2 observed in their methionine S ‐ oxide analogues. Metal complexes were observed forming at 10 −2 m to 10 −4 m but not at lower concentrations (10 −5 m to 10 −8 m ). Mass spectrometry data confirmed that metal binding strength varied by metal in the order Zn( CH 3 COO ) 2 <Pb( CH 3 COO ) 2 <Zn SO 4 <Cd( NO 3 ) 2 .