title: HTLV-I protease cleavage of P19/24 substrates is not dependent on NaCl concentration.
abstract: Understanding the factors that affect the activity of Human T-cell Leukemia Virus type I (HTLV-I) protease is essential for the discovery of inhibitors to be used for the treatment of HTLV-I infection, but little has been reported on the protease to date. Here we report the production of HTLV-I protease in purified yields greater than 150 mg/L, determination of its extinction coefficient, and determination of the optimum conditions for cleavage of the p19/24 substrates (DABCYL)-(GABA)-PQVL-Nph-VMH-(EDANS), (DABSYL)-(GABA)-PQVL-Nph-VMH-(EDANS), and (DABSYL)-(GABA)-PQVLPVMH-(EDANS). The highest activity was found at pH 5.2-5.3 and 37 degrees C. There was no effect on activity upon change in sodium chloride concentration from 0 to 1500 mM. The values of K(m) and k(cat) for cleavage of these substrates by the protease with and without the histidine tag were determined.
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
authors.forename: Julie J
authors.initials: JJ
authors.lastname: Ha
authors.forename: David A
authors.initials: DA
authors.lastname: Gaul
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Mariani
authors.forename: Y Shirley
authors.initials: YS
authors.lastname: Ding
authors.forename: Richard A
authors.initials: RA
authors.lastname: Ikeda
authors.forename: Suzanne Beckham
authors.initials: SB
authors.lastname: Shuker
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009842:Oligopeptides / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature
chemical_list: D005456:Fluorescent Dyes; D009842:Oligopeptides; D012965:Sodium Chloride; D016282:Aspartic Acid Endopeptidases; C079711:HTLV-1 protease