title: Purification and characterization of a new xylanase from Acrophialophora nainiana.
abstract: A new xylanase activity (XynII) was isolated from liquid state cultures of Acrophialophora nainiana containing birchwood xylan as carbon source. XynII was purified to apparent homogeneity by gel filtration and ion exchange chromatographies. The enzyme was optimally active at 55 degrees C and pH 7.0. XynII had molecular mass of 22630+/-3.0 and 22165 Da, as determined by mass spectrometry and SDS-PAGE, respectively. The purified enzyme was able to act only on xylan as substrate. The apparent K(m) values on soluble and insoluble birchwood xylans were 40.9 and 16.1 mg ml(-1), respectively. The enzyme showed good thermal stability with half lives of 44 h at 55 degrees C and ca. 1 h at 60 degrees C The N-terminal sequence of XynII showed homology with a xylanase grouped in family G/11. The enzyme did not show amino acid composition similarity with xylanases from some fungi and Bacillus amyloliquefaciens.
authors.affiliation: Laboratório de Enzimologia, Departamento de Biologia Celular, Universidade de Brasília, Campus Universitario, Asa Norte, 70910-900 Brasilia-DF, Brazil.
authors.forename: B C
authors.initials: BC
authors.lastname: Salles
authors.forename: R B
authors.initials: RB
authors.lastname: Cunha
authors.forename: W
authors.initials: W
authors.lastname: Fontes
authors.forename: M V
authors.initials: MV
authors.lastname: Sousa
authors.forename: E X
authors.initials: EX
authors.lastname: Filho
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D003904:Mitosporic Fungi / Q000201:enzymology*; D008969:Molecular Sequence Data; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase