| Title |
Purification and Characterization of the α-Glucosidase Produced by Thermophilic Fungus Thermoascus aurantiacus CBMAI 756 |
| Author |
Ana Flávia Azevedo Carvalho*, Maurício Boscolo, Roberto da Silva, Henrique Ferreira, and Eleni Gomes |
| Address |
Laboratory of Bichemistry and Applied Microbiology, São Paulo State University-Unesp, São José do Rio Preto 15054-000, Brazil |
| Bibliography |
Journal of Microbiology, 48(4),452-459, 2010,
|
| DOI |
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| Key Words |
α-glucosidase, T. aurantiacus, termostable enzyme, transglycosylation reaction, purification |
| Abstract |
Αn α-glucosidase enzyme produced by the fungus Thermoascus aurantiacus CBMAI 756 was purified by ultra filtration, ammonium sulphate precipitation, and chromatography using Q Sepharose, Sephacryl S-200, and Superose 12 columns. The apparent molecular mass of the enzyme was 83 kDa as determined in gel electrophoresis. Maximum activity was observed at pH 4.5 at 70°C. Enzyme showed stability stable in the pH range of 3.0-9.0 and lost 40% of its initial activity at the temperatures of 40, 50, and 60°C. In the presence of ions Na+, Ba2+, Co2+, Ni2+, Mg2+, Mn2+, Al3+, Zn2+, Ca2+ this enzyme maintained 90-105% of its maximum activity and was inhibited by Cr3+, Ag+, and Hg2+. The enzyme showed a transglycosylation property, by the release of oligosaccharides after 3 h of incubation with maltose, and specificity for short maltooligosaccharides and α-PNPG. The Km measured for the α-glucosidase was 0.07 μM, with a Vmax of 318.0 μmol/min/mg. |
