Purification and characterization of endo-xylanases from Aspergillus Niger. III. An enzyme of PL 365
An endo-xylanase (1,4-..beta..-D-xylan xylanohydrolase, EC 3.2.1.8) from Aspergillus niger was purified to homogeneity 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 DEAE-Sephadex A-25 at pH 5.15. The enzyme was active on soluble xylan, on insoluble xylan only after arabinosyl-initiated branch points were removed, and on xylooligosaccharides longer than xylotetraose. There was slight activity on carboxymethyl-cellulose, arabinogalactan, glucomannan, and p-nitrophenyl-..beta..-D- glucopyranoside. The main products of the hydrolysis of soluble and insoluble xylan were oligosaccharides of intermediate length, especially the tri- and pentasaccharides. The isolectric point of the enzyme was 3.65. It had a molecular weight of 2.8 x 10/sup 4/ by SDS-gel electrophoresis, and was high in acidic amino acids but low in those containing sulfur. Highest activity in a 20-min assay at pH 5 was between 40 and 45 degrees C, with an activation energy up to 40 degrees C of 11.1 kJ/mol. The optimum pH for activity was at 5.0. The enzyme was strongly activated by Ca/sup 2 +/. 15 references.
- Research Organization:
- Iowa State Univ., Ames
- OSTI ID:
- 5199351
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 27:4
- Country of Publication:
- United States
- Language:
- English
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09 BIOMASS FUELS
XYLANASE
ENZYME ACTIVITY
PURIFICATION
ACTIVATION ENERGY
ASPERGILLUS
CHEMICAL PREPARATION
CHROMATOGRAPHY
ENZYMATIC HYDROLYSIS
MOLECULAR WEIGHT
OLIGOSACCHARIDES
PH VALUE
XYLANS
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
ENERGY
ENZYMES
FUNGI
GLYCOSYL HYDROLASES
HEMICELLULOSE
HYDROLASES
HYDROLYSIS
LYSIS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
SYNTHESIS
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