title: Purification and characterization of a novel cellulase-free xylanase from Acrophialophora nainiana.
abstract: A beta-xylanase (XynIII) of Acrophialophora nainiana was purified to homogeneity from the culture supernatant by ultrafiltration and a combination of ion exchange and gel filtration chromatographic methods. It was optimally active at 55 degrees C and pH 6.5. XynIII had molecular masses of 27.5 and 54 kDa, as estimated by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. The purified enzyme hydrolyzed preferentially xylan as the substrate. The half-lives of XynIII at 50 and 60 degrees C were 96 and 1 h, respectively. It was activated by L-tryptophan, dithiothreitol, 5,5-dithio-bis(2-nitrobenzoic acid, L-cysteine and beta-mercaptoethanol and strongly inhibited by N-bromosuccinimide. The presence of carbohydrate was detected in the pure XynIII.
authors.affiliation: Laboratório de Enzimologia, Departamento de Biologia Celular, Universidade de Brasília, Brazil.
authors.forename: Orlando Aparecido Vieira
authors.initials: OA
authors.lastname: Cardoso
authors.forename: Edivaldo Ximenes Ferreira
authors.initials: EX
authors.lastname: Filho
mesh_terms: D002480:Cellulase; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D003904:Mitosporic Fungi / Q000201:enzymology*; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D014990:Xylans; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002480:Cellulase