Identification and characterization of a novel antioxidant peptide from feather keratin hydrolysate

To improve the potential value of feather, which is a valuable protein resource, we have separated and identified antioxidant peptide(s) from feather hydrolysate. Feather hydrolysate was prepared by fermentation with Bacillus subtilis S1-4. Antioxidative peptides were separated by sequential acid precipitation, cation exchange, and reversed-phase fast performance liquid chromatography. Finally, a peptide with antioxidative activity was identified as Ser-Asn-Leu-Cys-Arg-Pro-Cys-Gly by MALDI time-of-flight (TOF)/TOF analysis, and determined to represent a portion of feather keratin near its N-terminal. A synthesized peptide with the same sequence was used to characterize its antioxidative properties, including scavenging free radicals, reducing power, and Fe2+ chelation. In terms of the peptide's amino acid composition, the antioxidative activity might be mainly attributed to Cys and other amino acid residues. Feather keratin is a good source for the quantitative preparation of antioxidative peptides.