title: Hatching enzyme from the sea-squirt Ciona intestinalis: purification and properties.
abstract: We have purified a 34 kDa hatching enzyme from the water in which the embryos of the sea-squirt Ciona intestinalis hatch. This enzyme was obtained in homogeneous form as judged from SDS-PAGE and HPLC gel filtration. The enzyme possesses proteolytic activity and is able to digest the chorion of the egg of C. intestinalis. It is a metalloproteinase and contains one atom of Zn per molecule. The optimum pH is 8.5. The enzyme shows hydrolytic activity towards the -CO-NH- bonds, which are hydrolyzed by the members of the serine proteinase family. It has a trypsin-like activity in that it cuts the bond of Arg and Lys at P1 position of the scissile bond -P1-P1', but it differs from trypsin insofar as it hydrolyzes the peptide bond on either side of Arg and Lys. The purified enzyme is inhibited by the common metal-chelators and by the classical trypsin proteinase inhibitors. The apparent K(m) values at 37 degrees C and pH 8.5 toward tosyl-Gly-Pro-Arg-NHNap, tosyl-Gly-Pro-Lys-NHNap and Bz-Arg-Gly-Arg-NHNap were 0.125, 0.5 and 2.5 mM, respectively. The results obtained in this study suggest that the hatching enzyme from C. intestinalis exhibits both trypsin-like activity and metalloproteinase activity.
authors.affiliation: Department of Biochemistry and Molecular Biology, Stazione Zoologica A. Dohrn, Napoli, Italy.
authors.forename: A
authors.initials: A
authors.lastname: D'Aniello
authors.forename: M
authors.initials: M
authors.lastname: de Vincentiis
authors.forename: M M
authors.initials: MM
authors.lastname: Di Fiore
authors.forename: S
authors.initials: S
authors.lastname: Scippa
mesh_terms: D000818:Animals; D002938:Ciona intestinalis / Q000196:embryology / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D008666:Metalloendopeptidases; C024344:envelysin