Purification Of Venoms And Their Proteases Activity And Antioxidant Activity From Two Large Kinds Of Jellyfish

Jellyfish is a rich source of marine biology not only from distribution but also from species in China. Reported jellyfish venoms mainly contained in the tentacles and nematocysts, are types of polypeptide venoms with unique structures. The difference of jellyfish species results in different structure and bioactivities of jellyfish toxin. The isolation and purification, concentration, physical and chemical characters, bioactivities such as protease activity and antioxidant activity of venom from jellyfish Rhopilema esculentum Kishinouy (R. esculentum) and Cyanea nozakii Kishinouye (C. nozakii) were investigated in this study.To effectively enhance the concentration of the venom from jellyfish R. esculentum, five concentration methods were employed to concentrate it in the study. The results showed that the concentration of the venom concentrated with lyophilization and dissolved with 50 mmol/L PBS (LT50) was 4.6 times of that of the venom before concentration (CT). And its recovery ratio was 34.9%. The kinds of the proteins had invariability. The folds of concentration obtained from methods of freezing and gel didn't reach to 2.The venom of R. esculentum was chromatographed on a DEAE Sepharose Fast Flow column. There was only one protein in the component which was eluted by PBS (0.02 mol/L,pH 8.0) containing 0.4 mol/L NaCl. The protein was histone 4 afterN-terminal analysis. There were two components isolated by gel and five to nine components isolated by CM Sepharose Fast Flow chromatography from the venom of R. esculentum. There were two components isolated by Sephadex G-50,G-100 and three components isolated by DEAE Sepharose Fast Flow from the venom of C. nozakii.The venom from R. esculentum had high protease activity. The protease activity was affected by some chemical and physical factors such as temperature, pH values and divalent metal cations. Zn²⁺, Mg²⁺, Mn²⁺ in sodium phosphate buffer (0.02 mol/L, pH 8.0 ) could increase protease activity. Mn²⁺ had the best effects among the three metal cations. EDTA could increase protease activity. O-phenanthroline and glycerol played an important part in inhibiting protease activity and their maximal inhibiting rates were 87.5% and 82.1%, respectively, so they could be used as protease inhibitor to improve the instability of the venom.The in vitro antioxidant activities of venom from R. esculentum were investigated and the results showed that all five samples had antioxidant activities. They had strong scavenging effect on superoxide anion radical and hydroxyl radical. The reducing power was very low and the metal chelating capability was obvious. The proteins showed strong scavenging activity on hydroxyl radical and the scavenging effect was 85% at the concentration of 41μg/mL. However, the proteins had low scavenging effect on superoxide anion radical, and the scavenging effect of the proteins was 48.6% at the concentration of 77.7μg/mL. The proteins showed strong reducing power, but had no metal chelating activity. The radical scavenging activity was stable at high temperature. The results showed that the hudrosulfide contained in CP wasn't the mainly factor on the antioxidant activity. In conclusion, the venom from R. esculentum and C. nozakii had significant protease activity, could effectively scavenge active oxygen radicals. These results established foundations for study and utilization jellyfish toxin in the future.