Purification and properties of a thermostable xylanase GH 11 from Penicillium occitanis Pol6.
An extracellular, endo-β-1,4-xylanase was purified to homogeneity from the culture filtrate of the filamentous fungus Penicillium occitanis Pol6, grown on oat spelt xylan. The purified enzyme (PoXyn2) showed a single band on SDS-PAGE with an apparent molecular weight of 30 kDa. The xylanase activity was optimal at pH 3.0 and 65 °C. The specific activity measured for oat spelt xylan was 2,368 U mg(-1). The apparent K(m) and V(max) values were 8.33 mg ml(-1) and 58.82 μmol min(-1) ml(-1), respectively, as measured on oat spelt xylan. Thin-layer chromatography experiments revealed that purified PoXyn2 degrades xylan in an endo-fashion releasing xylobiose as main end product. The genomic DNA and cDNA encoding this protein were cloned and sequenced. This PoXyn2 presents an open reading frame of 962 bp, not interrupted by any introns and encoding for a mature protein of 320 amino acids and 29.88 kDa.
Unité Enzymes et Bioconversions, Ecole Nationale d'Ingénieurs de Sfax, University of Sfax, BP 1173, 3038 Sfax, Tunisia. dorra_driss@yahoo.fr
Dorra
D
Driss
Fatma
F
Bhiri
Mariem
M
Siela
Raoudha
R
Ghorbel
Semia Ellouz
SE
Chaabouni
D000595:Amino Acid Sequence; D001483:Base Sequence; D005591:Chemical Fractionation; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D010407:Penicillium / Q000201:enzymology*; D017421:Sequence Analysis; D013696:Temperature; D014990:Xylans / Q000378:metabolism
D008670:Metals; D014990:Xylans; D043364:Endo-1,4-beta Xylanases