Identification of antioxidative oligopeptides derived from autolysis hydrolysates of sea cucumber (Stichopus japonicus) guts

Abstract

Oligopeptides were prepared from the guts of sea cucumber Stichopus japonicus by autolysis method. Optimum autolysis conditions for preparing oligopeptides from the guts of sea cucumber were determined by response surface methodology using a central composite rotatable design. The effects of two independent variables, namely temperature and pH, on the response of trichloroacetic acid-soluble oligopeptides (mg/g on dry basis) were investigated. Regression analysis indicated that more than 95 % of the variation could be explained by the fitted models. Temperature at 48.30°C and pH at 4.43 were found to be the optimal conditions to obtain oligopeptides from the guts of sea cucumber. The autolysis hydrolysates prepared at the optimized conditions were further fractionated into four major fractions (I-IV) by size exclusion chromatography on a Sephadex G-15 column. Fraction IV, which exhibited the highest DPPH radical scavenging capacity, Fe 2? -chelating ability and protective effect against hydroxyl radical-induced DNA damage, was then analyzed by ESI-MS for molecular mass determination and ESI-MS/MS for the characterization of peptides. Two tetrapeptides (Val-Thr-Pro-Tyr and Val-Leu-Leu-Tyr) and a hexapeptide (Val-Gly-Thr-Val-Glu-Met) were found to exhibit protective effects against hydroxyl radical-induced DNA damage. These results suggest that antioxidant oligopeptides derived from the guts of sea cucumber by autolysis method could be utilized for functional foods.

Physicochemical and functional properties of protein isolate from sea cucumber ( Stichopus japonicus ) guts

“…As sea cucumber guts are easily subjected to autolysis, the SCGPI has been distributed in the range with low molecular weight. According to our previous study, the protein degradation to peptide was limited in sea cucumber gut (Zheng et al, 2012). Therefore, the SCGPI has the low molecular weight in the form of protein.…”

“…During the processing of sea cucumber, some byproducts, such as sea cucumber guts and eggs, are usually abandoned as industrial wastes, which not only results in the waste of resources but also brings serious environmental pollution. Research has shown that the sea cucumber gut is rich in protein (Zheng et al, ), and can be a source for the preparation of protein isolate.…”

Characterization of proteolysis in muscle tissues of sea cucumber Stichopus japonicus

“…To characterize the autolysis of sea cucumbers, several cysteine protease have been purified from sea cucumbers, including cysteinelike protease (15), cathepsin L-like enzyme (16,17), and cathepsin B (18). Via an autolysis reaction, three antioxidant peptides were obtained from the sea cucumber guts (19). As a continuation of previous studies, in the present study, the proteolysis in muscle tissues of S. japonicus was characterized.…”

Biological activities and biomedical potential of sea cucumber (Stichopus japonicus): a review

“…The IC 50 value of superoxide and hydroxyl radicals were 442 and 285 μg/ml, respectively. Zheng et al (2012) identified an antioxidative oligopeptide from autolysis hydrolysates of S. japonicus guts. Two tetrapeptides Val-Thr-Pro-Tyr (497 Da), ValLeu-Leu-Tyr (507 Da) and a hexapeptide Val-Gly-ThrVal-Glu-Met (635 Da) were elucidated by ESI-MS/MS and exhibited antioxidant activities by the protection of hydroxyl radical-induced DNA damage.…”