Partial purification and identification of a metalloproteinase with anticoagulant activity from Rhizostoma pulmo (Barrel Jellyfish)

- A metalloproteinase is described from the tentacle extract of Barrel Jellyfish.
- The tentacle extract digested fibrinogen, fibrin, azocasein and gelatin.
- Tentacle extract also inhibited ADP induced platelet aggregation in vitro.
- The metalloprotease activity seems to be due to the presence of Zn2+.
- The described metalloproteinase is named Rhizoprotease (∼95 kDa).

Rhizostoma pulmo (Barrel Jellyfish) is one of the commonly found jellyfishes on the South-Goan coast of India. Here we present characterization of R. pulmo tentacle extract. The tentacle extracts were found to be capable of affecting the hemostatic system at three different levels, as it exhibited fibrinogenolysis, fibrinolysis and inhibition of ADP induced platelet aggregation. It preferentially cleaved the Aα chain of fibrinogen, followed by the Bβ chain and the γ chain. The tentacle extract also showed significant hemolytic activity against human RBCs and strong proteolytic activity for substrates like (azo) casein and gelatin. However, this proteolytic activity was completely inhibited by EDTA (metalloproteinase inhibitor) but not by PMSF (serine proteinase inhibitor). The extract was devoid of phospholipase activity. A semi-purified protein possessing fibrinogenolytic activity was obtained by a combination of ammonium sulphate precipitation and size exclusion HPLC. Atomic absorption analysis of this protein indicated presence of Zn2+ and treatment with metalloproteinase inhibitor caused complete loss of activity. A 95 kDa metalloproteinase was identified in this fraction and was named Rhizoprotease. Protein Mass Fingerprinting of Rhizoprotease indicates it to be a novel protein.