Purification and characterization of endo-xylanases from aspergillus Niger. II. An enzyme of PL 45

Journal Article · Mon Apr 01 00:00:00 EST 1985 · Biotechnol. Bioeng.; (United States)

DOI:https://doi.org/10.1002/bit.260270421· OSTI ID:5324274

Shei, J C; Fratzke, A R; Frederick, M M; Frederick, J R; Reilly, P J

A homogeneous endo-xylanase (1,4-..beta..-D-xylan xylano-hydrolase, EC 3.2.1.8) was obtained from a crude Aspergillus niger pentosanase by chromatography with Ultrogel AcA 54, SP-Sephadex C-25 at pH 4.5, DEAE-Sephadex A-25 at pH 5.4, Sephadex G-50, and SP-Sephadex C-25 with a gradient from pH 2.8 to pH 4.6. It was much more active on soluble than on insoluble xylan yielding large amounts of unreacted xylan and a mixture of oligosaccharides with chain lengths from two to six. No xylose or L-arabinose was produced. There was high activity on a xylopentaose through xylononaose mixture, but not on xylobiose, xylotriose, or xylotetraose. The enzyme had slight activity on untreated cellulose, carboxymethylcellulose, and pectin. Molecular weight was ca. 1.4 x 10/sup 4/, with an isoelectric point of 4.5 and an amino acid profile high in acidic but low in sulfur-containing residues. In a 25-min assay at pH 4.7, this endo-xylanase was most active at 45 degrees C, with an activation energy from 5 to 35 degrees C of 33.3 kJ/mol. The optimum pH for activity was 4.9. Decay in buffer was first order, with an activation energy at pH 4.7 from 48 to 53 degrees C of 460 kJ/mol. Optimum pH for stability was about 5.6, where the half-life at 48 degrees C in buffer was ca. 40 h.

• Research Organization: Iowa State Univ., Ames, IA
• OSTI ID: 5324274
• Journal Information: Biotechnol. Bioeng.; (United States), Vol. 27:4
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
09 BIOMASS FUELS
XYLANASE
ENZYME ACTIVITY
PURIFICATION
ACTIVATION ENERGY
ASPERGILLUS
CHEMICAL REACTION KINETICS
CHROMATOGRAPHY
ENZYMES
PH VALUE
PHYSICAL PROPERTIES
ENERGY
FUNGI
GLYCOSYL HYDROLASES
HYDROLASES
KINETICS
O-GLYCOSYL HYDROLASES
PLANTS
REACTION KINETICS
SEPARATION PROCESSES
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