Isolation and Characterization of Peptides with Antioxidant Activity Derived from Wheat Gluten.

Abstract

Peptides having potent antioxidant activity were separated from the hydrolysate of wheat gluten by ion-exchange and gel filtration chromatography. Peptides obtained by SP Sephadex C-25 chromatography of the most active fraction (WP-3) were further separated using reversed-phase high performance liquid chromatography. The amino acid sequences of these peptides were Leu-Gln-Pro-Gly-Gln-Gly-Gln-Gln-Gly and Ala-Gln-Ile-Pro-Gln-Gln.Keywords: wheat gluten, hydrolysate, peptide, antioxidant activityThe disease-preventing potential of naturally occurring substances in the diet is a main area of scientific interest. Antioxidants have attracted great attention for disease preventive effects because of lipid peroxidation which can lead to destabilization and disintegration of cell membranes, to many age-related diseases, to aging, and to cancer (Mcbrien & Slater, 1982). Recently, the involvement of free radicals and other oxidants in aging and in several diseases has been investigated in detail. Much physiological damage may be directly imputable to the hydroxyl radical, because it is highly reactive, and so many hydroxyl radicals produced in vivo react at or close to their site of formation. The biochemical literature is full of claims that reactive species are involved in different diseases (Southorn & Powis, 1988).Many proteins have been reported to have antioxidant activities against the peroxidation of lipids or fatty acids upon hydrolysis (Rival et al., 2001, Suetsuna, 2000Chen et al., 1998;Hattori et al., 1998;Bishov & Henick, 1972). Gluten has a unique amino acid composition, with Glu/Gln and Pro accounting for more than 50% of the amino acid residues. About 30% of gluten's amino acid residues are hydrophobic, and the residues contribute greatly to its ability to form protein aggregates by hydrophobic interactions and to bind nonpolar substances (Fennema, 1996). Since wheat gluten had strong affinity for oil and other nonpolar substances, we speculated that gluten's hydrolysate would have some protective effect on the degradation of fatty acid. In this study, we examined the antioxidant effects of peptic hydrolysate of wheat gluten, and the amino acid sequences of antioxidant peptides were determined. Materials and methodsMaterials Wheat gluten was purchased from Oriental Yeast (Tokyo). Pepsin (from porcine gastric mucosa, EC 3.4.23.1) was obtained from Merck (Darmstadt, Germany).Linoleic acid (~99%) and d-␣-tocopherol from Sigma Chemical (St. Louis, MO) were used as received. All other reagents were of analytical grade from Nacalai Tesque (Kyoto).Purification of peptides from wheat gluten Ten grams of wheat gluten was put in 100 ml of deionized water overnight and homogenized in 1 l of deionized water. The pH value of the homogenate was adjusted to 2.0 with 2 N HCl, and 0.3 g of pepsin was added. After 20 h of digestion at 37ºC, the hydrolysate was filtered to remove the residue and centrifuged at 20,000¥g for 20 min at 4ºC. The supernatant was applied to a Dowex 50W column (4.5¥20 cm, 50-100 mesh, H + form). The ...

Peptidomic study of Spanish blue cheese (Valdeón) and changes after simulated gastrointestinal digestion

“…Other peptides that were found in both digests are the β‐casein sequences VKEAMAPK f98–105, EMPFPK f108–113, reported as ACE‐inhibitors and YPVEPF f114–119, reported as opioid . The β‐casein region 106–119, that gave rise to the latter peptides, together with the domains 60–93 and 133–140 seem to be very resistant to gastrointestinal digestion in both SMP and cheese, probably due to the presence of Pro in their sequences .…”

“…From the α s1 ‐casein sequence, peptides f144–149 (AYFYPEL) and f143–149 (YFYPEL) were generated during digestion. Both peptides have been previously found to exert antioxidant activity , and mucin secretory activity in HT29‐MTX cells . In addition, the second one has demonstrated potent antihypertensive activity (Table ).…”

Selected Lactic Acid Bacteria Synthesize Antioxidant Peptides during Sourdough Fermentation of Cereal Flours

“…His at the N terminus acts mainly as a metal ion chelator, while at the C terminus His is an effective scavenger against various radicals (4). Four sequences have Ala or Leu at the N or C terminus, which was already shown to be a typical feature for antioxidant peptides (43,47). Amino acids with aromatic residues may donate protons to electron-deficient radicals.…”

Antihypertensive Properties of Plant Protein Derived Peptides

“…In another study, flaxseed protein was treated with thermolysin followed by pronase to produce antioxidant peptides [42]. Moreover, pepsin, pancreatin, neutrase and esperase have been used to produce antioxidative hydrolysates and peptides [13,42,51,56,57].…”