Showing papers on "Termitomyces clypeatus published in 1985"

An Inducible Xylanase of the Mushroom Termitomyces clypeatus Differing from the Xylanase/Amylase Produced in Dextrin Medium

Abstract: Summary: The mushroom Termitomyces clypeatus produces a single endoxylanase (1,4-β-D-xylan xylano-hydrolase, EC 3.2.1.8) in the presence of either dextrin or xylan as sole source of carbon. The enzymes produced in the two conditions are different. The enzyme induced by xylan has been purified 67-fold from the culture filtrate of T. clypeatus. The enzyme preparation gave a single protein band on SDS-PAGE, corresponding to a molecular weight of about 24000. The enzyme has an isoelectric point at pH 4·0 and acts on arabinoxylan and arabinogalactan, but not amylopectin or galactomannan. It shows maximum activity on xylan (1,4-β-linked D-xylopyranose units) at pH 3·5 and 55°C and is fairly stable up to 60°C. The K m for xylan is 4 mg ml-1. Hg2+, Fe2+ and Ag+ are the most potent inhibitors of the enzyme. The pH optimum and molecular weight of this inducible xylanase differ from those of the enzyme produced by the same organism grown in dextrin medium.