title: Antioxidant capacities of fractionated barley hordein hydrolysates in relation to peptide structures.
abstract: METHODS
  This study has revealed strong antioxidant activities of barley hordein hydrolysate fractions and investigated the relationships between antioxidant properties and structural features of hordein peptides.
  
  
  RESULTS
  Barley hordein fractions separated based on molecular weight and surface hydrophobicity demonstrated strong antioxidant bioactivities, especially ferrous ion chelating capacity. Structural studies revealed the poly-l-proline helix, β-turn, and β-sheet as the dominant structural elements in the large molecular weight fraction, while most of the small-sized peptides assumed unordered random coil conformation accompanied by a large amount of ionized carboxyl groups produced as a result of partial deamidation of glutamine residues during hydrolysis. A study of antioxidant capacity in relation to peptide structure indicated the contribution of hydrophobic residues in radical scavenging and the positive effect of ionized carboxyl groups together with Lys and Met in metal chelation activity. QPYPQ was identified as the most repeated sequence in potent RP-HPLC fractions, which might be a particular structural motif that plays a key role in scavenging free radicals.
  
  
  CONCLUSIONS
  Barley hordein with its unique sequence partitioning has potential to produce peptides with strong antioxidant bioactivities.
authors: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
authors: Fatemeh
authors: F
authors: Bamdad
authors: Lingyun
authors: L
authors: Chen
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002942:Circular Dichroism; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D005973:Glutamine / Q000737:chemistry; D005983:Glutens / Q000737:chemistry*; D001467:Hordeum / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007502:Iron Chelating Agents / Q000494:pharmacology; D008239:Lysine / Q000737:chemistry; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D011492:Protein Hydrolysates / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship; D014462:Ultrafiltration
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D010455:Peptides; D011492:Protein Hydrolysates; D005973:Glutamine; D005983:Glutens; D011392:Proline; D008239:Lysine