| Popis: |
Aqueous extracts of 25 marine sponge species (from coral reefs of Papua New Guinea) were screened for proteolytic activity. Only one sponge, Callyspongia schulzi, showed remarkable activity. A protease hydrolyzing casein as well as the synthetic substrate alpha-N-benzoyl-L-arginine ethyl ester was isolated from the sponge extract by gel filtration, ion-exchange and HPLC absorption chromatography. The enzyme was homogenous in SDS-PAGE exhibiting an apparent molecular weight of 80 kDa. Its pH optimum was in the range of 9-11, it was remarkably heat-stable and was not inhibited by phenylmethane sulfonylfluoride, soybean trypsin inhibitor, aprotinin or alpha1-antitrypsin, but by EDTA and 1,10-phenanthroline suggesting properties of a metalloprotease. The protease hydrolyzed the oxidized insulin B-chain between Arg22-Gly23 and Lys29-Ala30, similar to trypsin. |
