Structural Analysis of Antioxidative Peptides from Soybean β-Conglycinin

Protease hydrolyses of a soybean protein, β-conglycinin (7S protein), yielded antioxidative activity against the peroxidation of linoleic acid in an aqueous system at pH 7.0. Six antioxidative peptides were isolated from the hydrolysate prepared with protease S by size exclusion chromatography and reversed-phase HPLC. The amino acid sequences of the peptides were determined using a gasphase protein sequencer and electron spray mass spectrometry. The peptides were composed of 5–16 amino acid residues, including hydrophobic amino acids, valine or leucine, at the N-terminal positions, and proline, histidine, or tyrosine in the sequences.