Identification and primary characterization of specific proteases in the digestive juice of Archachatina ventricosa.
The profile of sedimentation on a 4-20% (w/v) linear sucrose gradient of the digestive juice of the mollusk Archachatina ventricosa revealed the presence of at least four specific proteases. A first peak, corresponding to a sedimentation coefficient of 3.9 S, contained two endoproteases that could be assayed, one with Leu-pNA and the other with Met-pNA. Their activity was maximal at pH 8.0 and increased in the presence of Ca(2+) ions. Both enzymes were inhibited by the chelating agent 1,10-phenanthroline but their thermal inactivation kinetics were different. A second protease peak was observed at 6.8 S and corresponded to a metallo-endoprotease that hydrolyzed with a maximal activity at pH 8.0 only the amide bonds of peptide substrates having a threonine residue at the P1' position. A last protease peak identified at 9.0 S contained a protease that preferentially acted on tripeptides, such as Val-Pro-Leu (diprotin B) and Thr-Val-Leu, releasing the C-terminal residue. Unlike the proteases identified in the two other peaks, its activity was maximal at acid pH (5.0) and was inhibited by the serine protease inhibitors. Together these results show the potential of A. ventricosa as a source of specific proteases.
Guionie
Olivier
O
Laboratoire de Biochimie, Unité de Recherche sur la Biocatalyse, CNRS FRE 2230, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, F 44322, Nantes Cedex 3, France.
Moallic
Claire
C
Niamké
Sébastien
S
Placier
Gaël
G
Sine
Jean Pierre
JP
Colas
Bernard
B
D000818:Animals; D004064:Digestive System / Q000201:enzymology*; D010450:Endopeptidases / Q000032:analysis / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008974:Mollusca / Q000201:enzymology*; D011489:Protein Denaturation; D013379:Substrate Specificity
D010450:Endopeptidases