title: Purification and properties of beta-xylosidase from Penicillium wortmanni.
abstract: A purification method for an extracellular beta-D-xyloside xylohydrolase, EC 3.2.1.37) induced in Penicillium wortmanni is described. It includes diafiltration, acetone precipitation, and hydroxylapatite chromatography. The enzyme has a molecular weight of about 100,000. Its pH optimum is at pH 3.3--4.0 and it is most stable at pH 5.0-6.0. Its isoelectric point is at pH 5.0. Sulfhydryl and histidine reagents are not inhibitory. The influence of added cations and anions is negligible. N-Bromosuccinimide oxidation of two to three tryptophan residues per molecule entails rapid inactivation. Glycon-specificity studies indicate strict requirements at C-2, C-3, C-4, and C-5, although alpha-L-arabinopyranosides are substrates. As the enzyme seems to hydrolyse xylooligosaccharides endwise, with retention of configuration in the reaction product, the enzyme is a true glycosidase, probably operating by a double-inversion mechanism.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D006026:Glycoside Hydrolases / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D010407:Penicillium / Q000201:enzymology*; D013379:Substrate Specificity; D014995:Xylosidases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D006026:Glycoside Hydrolases; D014995:Xylosidases