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Purification and some properties of endoglucanase from Glyptotermes xiamenensis
Author(s) -
Shi Y.,
Tao Y.M.,
Ma S.J.,
An G.,
Long M.N.,
Chen Q.X.
Publication year - 2010
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.2009.01467.x
Subject(s) - chromatography , hydrolysis , michaelis–menten kinetics , chemistry , enzyme , sephadex , enzyme assay , biochemistry
An endoglucanase (EGase) from Glyptotermes xiamenensis was purified by extraction with phosphate buffer solution and ammonium sulfate fractionation, and then chromatographed on DEAE Sepharose Fast Flow followed by Sephadex G‐100 columns. The purified enzyme was determined to be homogeneous by polyacrylamide gel electrophoresis (PAGE). Enzyme molecular weight was determined to be 44.8 kDa and the enzyme was a monomeric protein. The specific activity was determined to be 458.7 U/mg. The optimum pH and optimum temperature of the enzyme for the hydrolysis of carboxymethycellulose sodium (CMC‐Na) were investigated to be at pH 5.0 and at 40°C, respectively. The enzyme was stable over the pH range from 4.0 to 9.0 and at the temperature below 45°C. Kinetic behaviour of the enzyme in the hydrolysis of CMC‐Na followed Michaelis–Menten kinetics with constant ( K m ) of 7.2 mg/ml at pH 5.0 and 40°C. The activation energy was determined to be 49.3 KJ/mol. Chemical modification indicated that the residues of histidine, tryptophan and carboxylate were essential to the enzyme activity.