Purification and identification of intestinal mucosal cell proliferation-promoting peptides from Crassostrea hongkongensis

Abstract

Oyster peptides, together with polysaccharides, were found to protect the intestinal mucosal barrier against the harmful effects of 5-FU chemotherapy on rats in our previous study. However, whether oyster (Crassostrea hongkongensis) peptide can promote intestinal epithelia cell proliferation and migration alone is unknown. In this paper, oyster tissue was hydrolyzed using pepsin, trypsin, papain, bromelain, neutrase, flavorzyme, and alcalase protease. Among the hydrolysates that produced by trypsin showed the highest promoting effect on intestinal epithelia cell (IEC-6) proliferation and was fractionated into three molecular weight ultra-filtrates of > 10, 10–5, and < 5 kDa. The 10–5 kDa ultra-filtrate showed the highest promoting effect on cell proliferation, at 146.16 ± 6.56% (0.16 mg/ml), and was subjected to further purification. Two oyster peptides (F3-1 and F3-2) were purified from the 5–10 kDa ultra-filtrate by SEC and RP-HPLC. Their molecular mass and amino acid sequences were identified as VAPEEHPVLL (MW, 1102.5872 Da) and SYELPDGQVITIGNER (MW, 1789.9247 Da) by MALDI–TOF–MS/MS. Peptides F3-1 and F3-2 exhibited 150.81 ± 12.34% (5 µg/ml) and 151.73 ± 12.28% (6.25 µg/ml) promoting effects on IEC-6 proliferation, respectively, and both peptides showed greater promoting effects than the positive control (proglumide) at the same concentration under LPS stimulation culture conditions. This study indicated that oyster peptides could serve as a potential source of a functional food constituent for intestinal epithelium protection.