Rapidly and Efficiently Screening and Identification of Xanthine Oxidase Inhibitory Peptides From Protein Hydrolysate of Antarctic Krill

With increasing public awareness of gout and hyperuricemia, the quest for xanthine oxidase (XOD) inhibitors to alleviate elevated uric acid levels has emerged as a central approach in hyperuricemia treatment. Defatted Antarctic krill meal, a cost-effective byproduct of krill oil production, is enriched with high-quality protein. This study aimed to evaluate the inhibition of the peptides from protein hydrolysate of Antarctic krill against XOD. Alcalase was implemented for the enzymatic preparation of proteins, and the optimal hydrolysis conditions were optimised. Utilising affinity ultrafiltration and molecular docking techniques, innovative XOD inhibitory peptides were isolated and identified from the protein hydrolysate of defatted Antarctic krill meal (AKAP). The inhibitory activities of these peptides were validated in vitro. A total of 943 peptides were identified by LC-MS/MS analysis, and their binding affinity to XOD was assessed using molecular docking. Among the peptides screened, Leu-Pro-Pro-Tyr-Ser-Lys-Glu (LPPYSKE, 832.43 Da, IC₅₀ = 0.332 ± 0.05 mg/mL) exhibited the highest XOD inhibitory activity. Molecular docking results revealed that salt bridges, hydrocarbon bonding and π–alkyl groups significantly affected the interaction between XOD inhibitory peptides and key residues, namely, GLU802, PHE914 and PHE1009. Overall, these results underscore the potential of AKAP as a promising candidate for the development of functional foods against hyperuricemia.