title: The alkaline xylanase III from Fusarium oxysporum F3 belongs to family F/10.
abstract: Xylanase III from Fusarium oxysporum F3 was purified to homogeneity by ion-exchange chromatography and gel filtration. The enzyme has a molecular mass of 38 kDa, an isoelectric point of 9.5, and is maximally active on oat spelt xylan at pH 7 and 45 degrees C with a Km of 0.8 mg/mL. The xylanase displays remarkable stability at pH 9.0. It is not active on xylotriose but hydrolyzes the 4-methylumbelliferyl glycosides of beta-xylobiose and beta-D-glucopyranosyl-(1-->4)-beta-D-xylopyranose, and to a lower extent 4-methylumbelliferyl beta-cellobioside. When acted on xylooligosaccharides and xylan, analysis of reaction mixtures by high-pressure liquid chromatography shows preferred internal glycoside cleavage. Thus the purified enzyme appears to be a true endo-beta-1,4-xylanase. Partial amino acid analysis of xylanase III shows high sequence homology with xylanases of family F/10.
authors.affiliation: Department of Chemical Engineering, National Technical University of Athens, Greece. hristako@orfeas.chemeng.ntua.gr
authors.forename: P
authors.initials: P
authors.lastname: Christakopoulos
authors.forename: W
authors.initials: W
authors.lastname: Nerinckx
authors.forename: D
authors.initials: D
authors.lastname: Kekos
authors.forename: B
authors.initials: B
authors.lastname: Macris
authors.forename: M
authors.initials: M
authors.lastname: Claeyssens
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D043364:Endo-1,4-beta Xylanases; D004795:Enzyme Stability; D005670:Fusarium / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014995:Xylosidases / Q000737:chemistry / Q000145:classification* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D014995:Xylosidases; D043364:Endo-1,4-beta Xylanases