title: Establishment of an in vitro assay system for screening hepatitis C virus protease inhibitors using high performance liquid chromatography.
abstract: The hepatitis C virus (HCV) genome contains the code for a conserved, serine-type protease, called NS3, for the processing of the non-structural protein region of the viral polyproteins. Furthermore, a related protein, NS4A, is an effector or cofactor of NS3 protease activity in the cleavage of NS3-4A, NS4A-4B, NS4B-5A and NS5A-5B junctions. To establish an in vitro assay system for the screening of those enzyme inhibitors that inhibit the protease NS3-4A, we prepared a maltose-binding protein-NS3-NS4A fusion protein and a synthetic peptide substrate that mimics the NS5A-5B junction. Cleavage of the synthetic peptide was analyzed by reversed-phase high performance liquid chromatography (HPLC). We showed that the enzymatic activity of the NS3-NS4A fusion protein was enhanced in comparison to the NS3 protein alone. The assay conditions for optimum NS3-4A protease activity were determined to be pH 7.6 and 37 degrees C. In addition, we evaluated several protease inhibitors using the same HPLC assay system. The activity of HCV protease NS3-4A was inhibited by 2714.4 microM diisopropyl fluorophosphate, 270.8 microM N-tosyl-L-lysyl chloromethyl ketone, and 825.5 microM chymostatin. The results of the present study indicated that the synthetic peptide substrate and HPLC assay system are suitable for studying HCV protease activity and may facilitate the development of anti-HCV therapeutic reagents.
authors.affiliation: Rational Drug Design Laboratories, Fukushima 960-12, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sudo
authors.forename: H
authors.initials: H
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Yamaji
authors.forename: K
authors.initials: K
authors.lastname: Konno
authors.forename: S
authors.initials: S
authors.lastname: Shigeta
authors.forename: T
authors.initials: T
authors.lastname: Kaneko
authors.forename: T
authors.initials: T
authors.lastname: Yokota
authors.forename: K
authors.initials: K
authors.lastname: Shimotohno
mesh_terms: D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D016174:Hepacivirus / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D066298:In Vitro Techniques; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000998:Antiviral Agents; D002352:Carrier Proteins; D017931:DNA Primers; D004279:DNA, Viral; D058619:Maltose-Binding Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D015842:Serine Proteinase Inhibitors; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C093542:NS4 protein, hepatitis C virus