Abstract: We aimed to explore the protective effects of oyster protein-derived peptides against acute alcoholic liver disease (ALD) in mice and to screen for potential bioactive peptides with alcohol-detoxifying and liver-protecting effects. Oyster protein was extracted and hydrolyzed by two different enzymes, neutral protease and alkaline protease, into peptides. The degree of hydrolysis, molecular mass distribution, and amino acid composition of the peptides obtained after different hydrolysis times were determined. Using an acute ALD mouse model, we evaluated the ameliorative effects of these peptides on acute ALD by measuring alanine aminotransferase (ALT), aspartate aminotransferase (AST) in the serum, and alcohol dehydrogenase (ADH), acetaldehyde dehydrogenase (ALDH), superoxide dismutase (SOD), glutathione (GSH), triglyceride (TG), and malondialdehyde (MDA) in the liver, as well as conducting pathological examination of the liver. Furthermore, peptide fractions with significant protective activity against liver injury were identified by mass spectrometry (MS) and screened. The results showed that compared with the model group, the activities of ALT and AST in the serum and the contents of MDA and TG in the liver of the peptide-treated groups was significantly decreased, the activities of SOD, GSH, ADH, and ALDH in the liver was markedly increased, and the pathological state of the liver was obviously ameliorated. Among all tested peptides, the peptides obtained after 2 and 4 h hydrolysis with alkaline protease (A-2 h) and neutral protease (N-4 h), respectively were found to be the most effective. Moreover, MS analysis identified 1 536 peptides in hydrolysate A-2 h and 1 782 peptides in hydrolysate N-4 h. After activity prediction and screening, ten oyster peptides with high activity were obtained. Molecular docking results showed that FAPPR, RFFYR, and FPGQR had strong binding affinity to ADH, indicating their potential for alcohol detoxification and liver protection. Subsequent in vitro experiments confirmed that all three peptides had an activating effect on ADH. In summary, this study provides ideas for the development of oyster-based therapeutic drugs against ALD.

Key words: oyster; acute alcoholic liver disease; bioactive peptides; alcohol dehydrogenase; molecular docking