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

Journal Article · Mon Apr 01 04:00:00 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), Journal Name: Biotechnol. Bioeng.; (United States) Vol. 27:4; ISSN BIBIA
• Country of Publication: United States
• Language: English

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