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Extracellular β‐ D ‐glucosidase from Chaetomium thermophilum var. coprophilum : production, purification and some biochemical properties
Author(s) -
Venturi Leandra Lórice,
de Lourdes Polizeli Maria,
Terenzi Héctor Francisco,
dos Prazeres Melo Furriel Rosa,
Jorge João Atílio
Publication year - 2002
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/1521-4028(200203)42:1<55::aid-jobm55>3.0.co;2-#
Subject(s) - extracellular , chaetomium , chemistry , biochemistry , enzyme , food science , microbiology and biotechnology , biology , penicillium
The thermophilic fungus Chaetomium thermophilum var. coprophilum produced large amounts of extracellular and intracellular β‐glucosidase activity when grown on cellulose or cellobiose as carbon sources. The presence of glucose in the culture medium drastically decreased the level of β‐glucosidase activity, while cycloheximide prevented the induction of the extracellular enzyme activity by cellobiose. An extracellular β‐glucosidase induced by avicel was purified by a procedure involving acetone precipitation and chromatography on two DEAE‐cellulose columns. The purified enzyme was a basic protein, with a carbohydrate content of 73%. The deglycosylated enzyme exhibited a molecular mass of 43 kDa, with pH and temperature optima of 5.5 and 65 °C respectively. The β‐glucosidase hydrolysed only cellobiose and p‐nitrophenyl‐β‐ D ‐glucopyranoside, exhibiting apparent K m values of 3.13 m M and 0.76 m M , respectively. The native purified enzyme was stable up to 2 hours at 60 °C, and its thermal stability was directly dependent on glycosylation.