Purification and Characterization of a [beta]-D-Xylosidase and an Endo-Xylanase from Wheat Flour.
A [beta]-D-xylosidase and an endo-xylanase were purified from European wheat (Triticum aestivum) flour. The [beta]-D-xylosidase had a molecular weight of approximately 64,000 and an isoelectric point of 5.5. It hydrolyzed p-nitrophenyl-[beta]-D-xylopyranoside and xylo-oligosaccharides and released D-xylose units from wheat arabinoxylan and oat spelts xylan. An endo-xylanase with a molecular weight of approximately 55,000 was also obtained and it consisted of a number of isoforms with isoelectric points between 4.0 and 5.0. The action of the isolated endo-xylanase depended on the degree of substitution of the polysaccharide. Unbranched polymers were preferentially hydrolyzed. Since xylo-oligosaccharides were not hydrolyzed, the enzyme appeared to need at least five or more consecutive unsubstituted xylose units. Finally, an [alpha]-L-arabinofuranosidase that hydrolyzed p-nitrophenyl-[alpha]-L-arabinofuranoside was partially purified.
Cleemput
G.
G
Nederlandse Organisatie voor Toegepast-Natuurwetenschappelyk Onderzoek, Nutrition and Food Research Institute, P.O. Box 360, NL-3700 AJ Zeist, The Netherlands (G.C., M.H.).
Hessing
M.
M
Van Oort
M.
M
Deconynck
M.
M
Delcour
J. A.
JA