title: Characterization of the norovirus 3C-like protease.
abstract: The recombinant 3C-like protease of Chiba virus, a Norovirus, expressed in Escherichia coli cells was purified and characterized as to effects of pH, temperature, salt contents, and SH reagents on its proteolytic activity. The optimal pH and temperature of the 3C-like protease for the proteolytic activity were 8.6 and 37 degrees C, respectively. Increased concentration (approximately 100 mM) of monovalent cations such as Na+ and K+ was inhibitory to the activity. Hg2+ and Zn2+ remarkably inhibited the protease activity, while Mg2+ and Ca2+ had no virtual effect. Several sulfhydryl reagents such as p-chloromercuribenzoic acid, methyl methanethiosulfonate, N-ethylmaleimide and N-phenylmaleimide also blocked the activity, confirming the previous result that cysteine residue(s) were responsible for the proteolysis.
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Someya
authors.forename: Naokazu
authors.initials: N
authors.lastname: Takeda
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyamura
mesh_terms: D000086042:3C Viral Proteases; D002414:Cations, Monovalent / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D029322:Norovirus / Q000201:enzymology*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature; D014764:Viral Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D002414:Cations, Monovalent; D004791:Enzyme Inhibitors; D008670:Metals; D011994:Recombinant Proteins; D013439:Sulfhydryl Reagents; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases