MilliporeSigma
  • A novel xylan degrading β-D-xylosidase: purification and biochemical characterization.

A novel xylan degrading β-D-xylosidase: purification and biochemical characterization.

World journal of microbiology & biotechnology (2012-07-26)
Michele Michelin, Simone C Peixoto-Nogueira, Tony M Silva, João A Jorge, Héctor F Terenzi, José A Teixeira, Maria de Lourdes T M Polizeli
ABSTRACT

Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular β-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. β-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 °C and 3.0-5.5, respectively. β-xylosidase was stable in acidic pH (3.0-6.0) and 70 °C for 1 h. The enzyme was activated by 5 mM MnCl₂ (28 %) and MgCl₂ (20 %) salts. The β-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-β-D-xylopyranoside, exhibiting apparent K(m) and V(max) values of 0.66 mM and 39 U (mg protein)⁻¹ respectively, and to a lesser extent p-nitrophenyl-β-D-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources, suggesting a novel β-D-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by β-xylosidase. TLC confirmed the capacity of the enzyme in hydrolyzing xylan and larger xylo-oligosaccharides, as xylopentaose.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Manganese(II) chloride tetrahydrate, BioReagent, suitable for insect cell culture
Sigma-Aldrich
Manganese(II) chloride solution, BioReagent, for molecular biology, storage temp.:room temp
Sigma-Aldrich
Manganese(II) chloride tetrahydrate, meets USP testing specifications
Sigma-Aldrich
Manganese(II) chloride, beads, 98%
Sigma-Aldrich
Manganese(II) chloride tetrahydrate, BioUltra, for molecular biology, ≥99.0% (KT)
Sigma-Aldrich
Manganese(II) chloride tetrahydrate, ACS reagent, ≥98%
Sigma-Aldrich
Manganese(II) chloride tetrahydrate, 99.99% trace metals basis
Sigma-Aldrich
Manganese(II) chloride 0.1 M solution
Sigma-Aldrich
Manganese(II) chloride, AnhydroBeads, −10 mesh, 99.999% trace metals basis
Sigma-Aldrich
Manganese(II) chloride, AnhydroBeads, −10 mesh, 99.99% trace metals basis
Sigma-Aldrich
Manganese(II) chloride tetrahydrate, ReagentPlus®, ≥99%
Sigma-Aldrich
Manganese(II) chloride, powder and chunks, ≥99% trace metals basis