title: Purification and characterization of a new 120 kDa alkaline proteinase of Trypanosoma cruzi.
abstract: A new alkaline proteinase activity was identified in cell-free extracts of Trypanosoma cruzi epimastigotes on the basis of its ability to hydrolyze the fluorogenic substrate N-Z-Gly-Gly-Arg-AMC. The optimal activity was at pH 8.0. After a three step-chromatography procedure using two anionic columns (DEAE-Sepharose and Mono Q) and a chromatofocusing column (Mono P), the proteolytic activity was associated with a single 120 kDa protein and was called Tc 120 proteinase. The molecular mass of the proteinase was confirmed by direct visualization of the proteolytic activity using a fluorometric assay on SDS-PAGE. The Tc 120 proteinase which also cleaves N-Z-Arg-AMC, N-Z-Phe-Arg-AMC and N-glutaryl-Gly-Arg-AMC substrates, is a cysteine-type proteinase with an unusual low sensitivity to E-64.
authors.affiliation: Laboratory of Biochemistry, University of Brasilia, Brazil.
authors.forename: J M
authors.initials: JM
authors.lastname: Santana
authors.forename: P
authors.initials: P
authors.lastname: Grellier
authors.forename: M H
authors.initials: MH
authors.lastname: Rodier
authors.forename: J
authors.initials: J
authors.lastname: Schrevel
authors.forename: A
authors.initials: A
authors.lastname: Teixeira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D015800:Protozoan Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D014349:Trypanosoma cruzi / Q000201:enzymology*
chemical_list: D010455:Peptides; D011480:Protease Inhibitors; D015800:Protozoan Proteins; D003546:Cysteine Endopeptidases; C076935:Tc 120 proteinase