title: Purification and characterization of two xylanases from Trichoderma longibrachiatum.
abstract: Two endoxylanases were purified from the culture medium of Trichoderma longibrachiatum. Both enzymes were highly basic, and lacked activity on carboxymethyl-cellulose. An enzyme of 21.5 kDa (xylanase A) had a specific activity of 510 U/mg protein, a Km of 0.15 mg soluble xylan/ml, possessed transglycosidase activity and generated xylobiose and xylotriose as the major endproducts from xylan or xylose oligomers. A larger enzyme of 33 kDa (xylanase B) had a specific activity of 131 U/mg protein, a Km of 0.19 mg soluble xylan/ml, lacked detectable transglycosidase activity and generated xylobiose and xylose as major endproducts from xylan and xylose oligomers. Xylotriose was the smallest oligomer attacked by both enzymes. In addition, xylotriose inhibited hydrolysis of xylopentanose by both enzymes, while xylobiose appeared to inhibit xylanase B, but not xylanase A.
authors.affiliation: State University of New York, College of Environmental Science and Forestry, Syracuse 13210.
authors.forename: J C
authors.initials: JC
authors.lastname: Royer
authors.forename: J P
authors.initials: JP
authors.lastname: Nakas
mesh_terms: D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006868:Hydrolysis; D007525:Isoelectric Focusing; D010449:Peptide Mapping; D014242:Trichoderma / Q000201:enzymology*; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000378:metabolism; D014994:Xylose / Q000378:metabolism
chemical_list: D014990:Xylans; D014994:Xylose; D006026:Glycoside Hydrolases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002918:Chymotrypsin