title: Stability and chemical modification of xylanase from Aspergillus sp. (2M1 strain).
abstract: The 2M1 strain of Aspergillus sp., which showed high extracellular xylanolytic activities in a pre-screening, was studied. Oat-spelt, birch, eucalyptus and pine xylans were used as xylanolytic inductors. The following activities were found at 50 degrees C in the presence of 1% xylan: 120 units/ml (oat-spelt xylan), 132 units/ml (birch xylan), 107 units/ml (eucalyptus xylan), 67 units/ml (pine xylan) and 137 units/ml (larch-wood xylan). Xylanase induced by pine xylan exhibited a higher stability than those induced by the other xylans. The stability was improved by addition of glycerol. In the crude extract, reagents which were found to affect xylanase activity were 1-ethyl-3-(3-dimethylaminopropyl)carbodi-imide for amidation of carboxylic groups and N-bromosuccinimide at a concentration of 0.5 mM for indole oxidation. Methylene Blue, butane-2,3-dione, N-acetylimidazole, chloramine-T and iodoacetate had little effect on the enzyme activity (more than 97% of the original activity remained).
authors.affiliation: Instituto de Quimica, Universidade Estadual de Campinas, S.P., Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Angelo
authors.forename: C
authors.initials: C
authors.lastname: Aguirre
authors.forename: E
authors.initials: E
authors.lastname: Curotto
authors.forename: E
authors.initials: E
authors.lastname: Esposito
authors.forename: J D
authors.initials: JD
authors.lastname: Fontana
authors.forename: M
authors.initials: M
authors.lastname: Baron
authors.forename: A M
authors.initials: AM
authors.lastname: Milagres
authors.forename: N
authors.initials: N
authors.lastname: Durán
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D002850:Chromatography, Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D013696:Temperature; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase