Some Properties of Xylanase and Xylobiase from Mixed Rumen Organisms

Publisher Website
Google Scholar
Abstract
Xylanase, free from xylobiase activity, was obtained from crude extracts of mixed rumen organisms by fractionation on DEAE-cellulose. Xylobiase preparations were also obtained, but some xylanase activity was associated with all such fractions isolated. Tris inhibits both xylanase and xylobiase activities, the latter being by far the more sensitive in most cases. Sodium, K, Li, and ammonium ions are all effective in partially overcoming the inhibition due to Tris. A number of compounds stereochemically related to Tris inhibit xylobiase, and an apparent relationship between structural properties and inhibitory activity is discussed. Xylobinase-free xylanase hydrolyses xylotriose and higher xylo-oligosaccharides, but not xylobiose, maltose, cellobiose, melibose, sucrose, lactose, cellulose or starch. The xylobiase preparations isolated attack a wide variety of di- and trisaccharides. There is no evidence that xylobiose is split by a phosphorolytic mechanism similar to that for the cleavage of cellobiose.