title: A novel protease from Entamoeba histolytica homologous to members of the family S28 of serine proteases.
abstract: Serine proteases are one of the biologically most important and widely distributed enzyme families. A protease capable of degrading the substrate Suc-AAF-AMC was isolated from axenically grown trophozoites of Entamoeba histolytica. The enzyme was purified by ion-exchange chromatography and electroelution, and appeared on 2D-PAGE as a spot of 60 kDa and pI of 4.65. Data obtained from zymogram suggest the active protease is present either as homodimer (130 kDa) or homotetramer (250 kDa). The optimal temperature of the enzyme was 37 degrees C, and it exhibited activity over a broad pH range. The protease was strongly inhibited by TPCK and chelating agents. The enzymatic activity was restored upon addition of calcium. BLAST analysis with the sequence of internal peptides of the protein revealed two open reading frames within the genome of E. histolytica, homologous to members of the family S28, clan SC of serine proteases.
authors.affiliation: Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Guanajuato, Guanajuato 36050, Mexico.
authors.forename: Minerva Paola
authors.initials: MP
authors.lastname: Barrios-Ceballos
authors.forename: Norma Angélica
authors.initials: NA
authors.lastname: Martínez-Gallardo
authors.forename: Fernando
authors.initials: F
authors.lastname: Anaya-Velázquez
authors.forename: David
authors.initials: D
authors.lastname: Mirelman
authors.forename: Felipe
authors.initials: F
authors.lastname: Padilla-Vaca
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000472:pathogenicity; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology
chemical_list: D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases