Isolation and Identification of Antioxidant Peptides from Enzymatically Hydrolyzed Soybean Protein

A high-purity antioxidant peptide SHP-1 was purified from enzymatically hydrolyzed soybean protein prepared under previously optimized conditions by high-efficiency strong anion exchange column (HiTrap Q HP), fast weak anion exchange column (HiTrap DEAE-FF) and preparative liquid chromatography. The molecular mass of the peptide was determined to be 741.41 Da by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The amino acid composition of SHP-1 was analyzed by an amino acid analyzer, revealing that it is composed of five amino acids. By using LC-MS/MS as well as comparison to the soybean protein database, the amino acid sequence of SHP-1 was determined to be IPPGVPY, which is derived from the G4 subunit of glycinin.