title: A continuous spectrophotometric assay for the hepatitis C virus serine protease.
abstract: The hepatitis C virus (HCV) encodes a chymotrypsin-like serine protease responsible for the processing of HCV nonstructural proteins and which is a promising target for antiviral intervention. Its relatively low catalytic efficiency has made standard approaches to continuous assay development only modestly successful. In this report, four continuous spectrophotometric substrates suitable for both high-throughput screening and detailed kinetic analysis are described. One of these substrates, Ac-DTEDVVP(Nva)-O-4-phenylazophenyl ester, is hydrolyzed by HCV protease with a second-order rate constant (kcat/Km) of 80,000 +/- 10,000 M-1 s-1. Together with its negligible rate of nonenzymatic hydrolysis under assay conditions (0.01 h-1), analysis of as little as 2 nM protease can be completed in under 10 min.
authors.affiliation: Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
authors.forename: R
authors.initials: R
authors.lastname: Zhang
authors.forename: B M
authors.initials: BM
authors.lastname: Beyer
authors.forename: J
authors.initials: J
authors.lastname: Durkin
authors.forename: R
authors.initials: R
authors.lastname: Ingram
authors.forename: F G
authors.initials: FG
authors.lastname: Njoroge
authors.forename: W T
authors.initials: WT
authors.lastname: Windsor
authors.forename: B A
authors.initials: BA
authors.lastname: Malcolm
mesh_terms: D000595:Amino Acid Sequence; D002863:Chromogenic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D016174:Hepacivirus / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry; D012697:Serine Endopeptidases / Q000032:analysis* / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013053:Spectrophotometry / Q000379:methods*; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000032:analysis / Q000378:metabolism; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D002863:Chromogenic Compounds; D009842:Oligopeptides; 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