Screening of xanthine oxidase inhibitory peptides by ligand fishing and molecular docking technology

Gout, as the second major metabolic disease after cardiovascular disease. Peptides have the advantages of natural and no side effects in the treatment and prevention of gout. This study aimed to screen xanthine oxidase (XOD) inhibitory peptides from Scophthalmus maximus protein as a drug basis for the treatment of gout. The specific results are as follows: Immobilization of xanthine oxidase 25.564 μg/mg by modified magnetic beads, and modified magnetic beads can be reused three times. Three decapeptides (FSLVHYAGTV, FTNEKLQQFF and WDDMEKIWHH) were screened, the IC50 were 3.741, 4.046 and 2.203 mg/mL. Circular dichroism and three-dimensional fluorescence spectra showed that the inhibitory peptide would change the helical structure of XOD and the internal hydrophobic environment. Molecular docking showed that the inhibitory effect of inhibitory peptides depends on the number of unique amino acid residues in the active center of XOD enzyme. In conclusion, this study provides a method for screening anti-gout peptides, which not only solves the problem of treating gout, but also realizes the high-value utilization of marine products. In addition, this method has substantial application value because of its low cost and simple operation.