Optimization of Preparation Techniques for Oligopeptides from Mauremys mutica and Its Potential to Inhibit SARS-CoV-2

ABSTRACT

This study aimed to explore the possibility of using Mauremys mutica oligopeptides as raw materials to develop a drug targeting the SARS-CoV-2 virus. M. mutica oligopeptides were prepared through the combined enzymatic hydrolysis of M. mutica meat using flavoenzyme and papain, and the optimal enzyme ratios, enzyme dosage, pH, and enzymatic hydrolysis time were determined using single-factor and orthogonal experiments. After separating the oligopeptide fractions via high-performance liquid chromatography-mass spectrometry (HPLC-MS), Peak Studio and Peptide Ranker were used for peptide sequence analysis and peptide activity prediction, respectively, to screen for oligopeptides with high bioactivity. Finally, the binding ability of oligopeptides with high predicted activity against the SARS-CoV-2 spike protein receptor-binding domain (RBD) was evaluated using molecular docking. The results show that the highest degree of hydrolysis (DH;42.56%) was obtained when M. mutica meat was treated with a flavoenzyme papain ratio of 73 and an enzyme dosage of 7% at pH 5.5 for 4 h. According to Peak Studio analysis, 510 peptides with an average local confidence (ALC) of > 90% were discovered. Six oligopeptides with high Peptide Ranker scores (LDFFK, LDFFKAL, FRVL, AFRVL, AGGKPFQ, and SPFRVT) were screened to dock with S protein. Their docking scores ranged from -138.50 to -169.68, and the lowest docking score (-169.68) was exhibited by LDFFKAL. Therefore, a high DH of M. mutica meat could be attained after process optimization, and a high inhibitory potential for SARS-CoV-2 was observed in the resulting M. mutica oligopeptides. © 2022 South China University of Technology. All rights reserved.