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In vivo anti-hyperuricemic and xanthine oxidase inhibitory properties of tuna protein hydrolysates and its isolated fractions
- He, Weiwei, Su, Guowan, Sun-Waterhouse, Dongxiao, Waterhouse, Geoffrey I.N., Zhao, Mouming, Liu, Yang
- Food chemistry 2019 v.272 pp. 453-461
- enzyme inhibition, ethanol, foods, high performance liquid chromatography, hydrogen bonding, hydrolysates, hyperuricemia, inhibitory concentration 50, molecular models, potassium, protein hydrolysates, rats, subtilisin, synthetic peptides, tuna, xanthine oxidase
- This study follows recent attempts to discover natural xanthine oxidase (XO) inhibitors from foods, focusing herein on under-researched fish proteins. The anti-hyperuricemic function of tuna flesh hydrolysate (TPH) produced using Alcalase 2.4L was confirmed in potassium oxonate-induced hyperuricemic rats. TPH was separated using 80 wt% aqueous ethanol. The ethanol-soluble fraction (ESF) abundant in small peptides (<1000 Da) afforded the highest XO inhibition. Separation of ESF by Sephadex G-15 and UPLC/MS/MS revealed 13 di-/tri-peptides (12 are newly identified XO inhibitors). Their XO inhibitory activities were assessed using corresponding synthetic peptides via an improved HPLC method. Results indicate that Phe-containing peptides were more potent XO inhibitors than Trp-containing peptides, with Phe-His having the highest XO inhibitory activity (IC50 = 25.7 mM). Molecular docking studies revealed the importance of two hydrogen bonds and one π-π stacking interaction with Phe-914 in XO for XO-peptide inhibitor binding. Phe-containing di-/tri-peptides could be potent XO inhibitors against hyperuricemia.