title: Purification and characterization of novel glucanases from Trichoderma harzianum ETS 323.
abstract: Trichoderma harzianum ETS 323 secretes two glucanases, a 23.5 kDa endoglucanase (EG Th1) and a 61 kDa exoglucanase (ExG Th1). They were identified by their hydrolysis products and were purified to homogeneity. The optimal temperature and pH for both EG Th1 (7.3-fold purification, 5.0% yield) and ExG Th1 (33.7-fold purification, 0.15% yield) were 50 °C and pH 4.5, respectively. The kinetic parameters of EG Th1 (K(m) = 23 mg mL(-1), V(max) = 294 μM min(-1), specific activity = 7.4 U mg(-1)) and ExG Th1 (K(m) = 85 mg mL(-1), V(max) = 385 μM min(-1), specific activity = 24.6 U mg(-1)) toward carboxymethyl cellulose were determined. Both enzymes favored CMC and maintained 100% activity for 10 days at 38 °C. KCl, MgCl(2), HgCl(2), and FeCl(3) showed approximately 30% inhibition against EG Th1 but not ExG Th1. They catalyzed transglycosylation of glucose in the presence of cellobiose, but ExG Th1 exhibited better activity and higher product diversity.
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, Changhua 51591, Taiwan.
authors.forename: Shu-Ying
authors.initials: SY
authors.lastname: Liu
authors.forename: Marthandam Asokan
authors.initials: MA
authors.lastname: Shibu
authors.forename: Hua-Jing
authors.initials: HJ
authors.lastname: Jhan
authors.forename: Chaur-Tsuen
authors.initials: CT
authors.lastname: Lo
authors.forename: Kou-Cheng
authors.initials: KC
authors.lastname: Peng
mesh_terms: D002475:Cellobiose / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013379:Substrate Specificity; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D002475:Cellobiose; D006026:Glycoside Hydrolases; D005947:Glucose