title: Protease activity in fractionated blood cells of the vanadium accumulating ascidian Phallusia mammillata.
abstract: Proteolytic activity was studied in the fractionated blood cells of the vanadium accumulating ascidian P. mammillata by separating the cells before measuring their activity. Cells were separated to avoid vanadocyte breakdown and subsequent vanadium diffusion into the assay medium. Our study revealed activity in the morula cell extract that was obtained by sonication and Centricon concentration. After removing part of the extract for enzyme activity assay the remainder was kept at 0 degrees C; it was later found that much of the protein in this latter fraction formed a sediment whereas the protease remained in solution. The serine-protease substrate specificity of the enzyme was measured and the results are discussed in relation to serine protease involvement in immune defense.
authors.affiliation: Dipartimento di Scienze Molecolari Agroalimentari, Facoltà di Agraria, Università degli Studi di Milano, via Celoria 2, I 20133, Milan, Italy. nicoletta.guerrieri@unimi.it
authors.forename: N
authors.initials: N
authors.lastname: Guerrieri
authors.forename: S
authors.initials: S
authors.lastname: Scippa
authors.forename: M
authors.initials: M
authors.lastname: Maietti
authors.forename: M
authors.initials: M
authors.lastname: de Vincentiis
authors.forename: P
authors.initials: P
authors.lastname: Cerletti
mesh_terms: D000818:Animals; D001773:Blood Cells / Q000166:cytology / Q000201:enzymology; D002458:Cell Fractionation; D002469:Cell Separation; D010450:Endopeptidases / Q000097:blood*; D014561:Urochordata / Q000378:metabolism*; D014639:Vanadium / Q000378:metabolism*
chemical_list: D014639:Vanadium; D010450:Endopeptidases