Etude comparative des protéases digestives de cinq espèces de crevettes pénéides

Abstract

The activities of the digestive proteases, trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidases A and B were investigated in the hepatopancreas of Penaeus japonicus, P. stylirostris, P. vannamei, P. merguiensis and P. monodon. Using synthetic substrates, no difference is found for trypsin, leucine aminopeptidase and carboxypeptidases A and B from the five species. Total protease activity is lower in P monodon and chymotrypsin activity is variable depending on the substrate used. Optimal pH, established for total proteases, trypsin, leucine aminopeptidase and carboxypeptidases A and B is alkaline for the five species. No proteolytic activity is found below pH 6. The electrophoretic patterns of soluble proteins, trypsin and leucine aminopeptidase are different for each species. For carboxypeptidase A no differences are observed except for P. japonicus for which three phenotypes are present. As shown by a dot immunobinding assay, the digestive extracts of the five species interact with a P. japonicus trypsin antiserum. Using rocket immunoelectrophoresis, no immunoprecipitation was found between the hepatopancreas extract of P. monodon and the antiserum.