Combining bioinformatic prediction and assay experiment to identify novel xanthine oxidase inhibitory peptides from Pacific bluefin tuna (Thunnus Orientalis)

Abstract

In this work, we aim to combine bioinformatic prediction with a special experiment to search xanthine oxidase (XOD) inhibitory peptides from myosin of Pacific bluefin tuna (Thunnus Orientalis). The program Peptide Cutter, Peptide Ranker, Peptide Property calculator, Toxin Pred, and Discovery Studio (DS) help us screen the probable sequence. The result indicated that peptide ICRK has the highest inhibition effect and the value of IC50 was 14.18 mg/mL. The IC50 of the other two peptides (FDAK and MMER) were 16.8mg/mL and 15.3 mg/mL respectively. Molecular simulation demonstrated that ICRK interacted with amino acid residues GLU802, PHE914, ALA1079, GLU1261, LYS771, LEU648, THR1010, VAL1011 and SER 876. The possible inhibition mechanism of peptides and enzyme was stated by DS. Peptide ICRK blocked the entrance to the hydrophobic channel and stopped xanthine going into the active site of XOD. MMER and FDAK have the similar mechanism with ICRK. Therefore, ICRK, FDAK and MMER can be considered as nature XOD inhibitory peptides and further utilized.