title: A cysteine protease isolated from the latex of Ficus microcarpa: purification and biochemical characterization.
abstract: A plant protease named microcarpain was purified from the latex of Ficus microcarpa by acetonic (20-40 % saturation) precipitation, Sephadex G-75 filtration, and Mono Q-Sefinose FF chromatography. The protease was purified with a yield of 9.25 % and a purification factor of 8. The molecular weight of the microcarpain was estimated to be 20 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The purified enzyme showed maximum activity at pH 8.0 and at a temperature of 70 °C. Proteolytic activity was strongly inhibited by dithio-bis-nitrobenzoic acid (DTNB), Hg(2+), and Cu(2+). The N-terminal amino acid sequence of the purified microcarpain "VPETVDWRSKGAV" showed high homology with a protease from Arabidopsis thaliana. Inhibition studies and N-terminal sequence classified the enzyme as a member of the cysteine peptidases family.
authors.affiliation: Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, 1173-3038, Sfax, Tunisia, ibtissemhamzamnif@yahoo.com.
authors.forename: Ibtissem Hamza
authors.initials: IH
authors.lastname: Mnif
authors.forename: Rayda
authors.initials: R
authors.lastname: Siala
authors.forename: Rim
authors.initials: R
authors.lastname: Nasri
authors.forename: Samiha
authors.initials: S
authors.lastname: Mhamdi
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
authors.forename: Alya Sellami
authors.initials: AS
authors.lastname: Kamoun
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D003545:Cysteine / Q000494:pharmacology; D057056:Cysteine Proteases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability / Q000187:drug effects; D030681:Ficus / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D007477:Ions; D007840:Latex / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000494:pharmacology; D059748:Proteolysis / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D013696:Temperature
chemical_list: D007477:Ions; D007840:Latex; D008670:Metals; D011480:Protease Inhibitors; D057056:Cysteine Proteases; D003545:Cysteine