title: Production, purification, and properties of an endoglucanase produced by the hyphomycete Chalara (Syn. Thielaviopsis) paradoxa CH32.
abstract: The hyphomycete Chalara (syn. Thielaviopsis) paradoxa produces endoglucanase activity during the late trophophase. The low molecular mass (35 kDa) endoglucanase purified from cultured broths works optimally at 37 degrees C and pH 5.0. The enzyme inactivates at pH below 3.0 and also at temperatures of 50 degrees C or higher, but it is stable at lower temperatures, including refrigeration temperature and freezing. The enzyme is inhibited by detergents, by EDTA, and by the divalent cations Hg(2+) and Ag(2+). It is also inhibited to some extent by 10 mM Zn(2+), Fe(2+), and Mg(2+), but it is stimulated by Mn(2+). Enzyme activity is not affected by reducing agents. In the presence of low concentrations of water miscible organic solvents (20%) endoglucanase activity is inhibited by 7% (for methanol) to 50% (for acetonitrile), and it is totally inhibited at higher solvent concentrations (50%). Enzyme activity is not affected by the water immiscible solvent ethyl acetate. Carboxymethylcellulose is the preferred substrate (K(m(app)) = 8.3 g/L; V(max(app)) = 1.1 microM/min). Hydrolysis of crystalline cellulosic substrates is very limited, but it is greatly enhanced by phosphoric acid swelling. The purified enzyme shows no activity toward disaccharides or aryl-glucosides. Its activity is inhibited by cellobiose.
authors.affiliation: Microbiology Division, Faculty of Experimental Sciences, University of Jaén, 23071 Jaen, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Lucas
authors.forename: A
authors.initials: A
authors.lastname: Robles
authors.forename: M T
authors.initials: MT
authors.lastname: García
authors.forename: G
authors.initials: G
authors.lastname: Alvarez De Cienfuegos
authors.forename: A
authors.initials: A
authors.lastname: Gálvez
mesh_terms: D000097:Acetonitriles / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D002480:Cellulase / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005296:Ferrous Compounds / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008628:Mercury / Q000494:pharmacology; D000432:Methanol / Q000494:pharmacology; D003904:Mitosporic Fungi / Q000201:enzymology*; D008970:Molecular Weight; D012834:Silver / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature; D015032:Zinc / Q000494:pharmacology
chemical_list: D000097:Acetonitriles; D002413:Cations, Divalent; D003902:Detergents; D004791:Enzyme Inhibitors; D005296:Ferrous Compounds; D012834:Silver; D004492:Edetic Acid; D002480:Cellulase; D008628:Mercury; D008274:Magnesium; D015032:Zinc; D000432:Methanol; C032159:acetonitrile