title: Identification and characterization of a protease produced by Vibrio parahaemolyticus in iron-limited medium.
abstract: Two proteolytic proteins (about 43 and 90 kDa) were produced by clinical strains of Vibrio parahaemolyticus cultured in iron-limited medium. The 43 kDa-protease was partially purified by ammonium sulfate precipitation, ultrafiltration fractionation and DEAE-Sephacel chromatography. This protease had an optimum pH range of 7 to 8, and an optimum reaction temperature of about 40 degrees C. It was heat-labile, being partially inactivated by heat-treatment at 60 or 90 degrees C for 10 min. The protease hydrolyzed casein, gelatin, elastin, collagen and hemoglobin. As a chymotrypsin-like protease, it was inhibited only by the chymostatin among seven protease inhibitors tested. Activity of this protease was partially inhibited by 1 mM of Co2+, Cu2+, Zn2+ and Hg2+ and slightly enhanced by Ca2+ and Ba2+. It was completely inactivated by orthophenanthroline (OPA), and the OPA-inactivated sample was partially reactivated by Ca2+ and Fe2+. In conclusion, this 43-kDa protease of V. parahaemolyticus was an unstable neutral chymotrypsin-like metalloprotease; Ca2+ and/or Fe2+ was essential for its activity or stability.
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan, R.O.C.
authors.forename: H C
authors.initials: HC
authors.lastname: Wong
authors.forename: J T
authors.initials: JT
authors.lastname: Shyu
mesh_terms: D003470:Culture Media; D010450:Endopeptidases / Q000096:biosynthesis* / Q000633:toxicity; D007501:Iron / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D014736:Vibrio parahaemolyticus / Q000201:enzymology* / Q000472:pathogenicity
chemical_list: D003470:Culture Media; D011480:Protease Inhibitors; D007501:Iron; D010450:Endopeptidases