Title |
Characterisation of a recombinant β-xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris
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Published in |
AMB Express, August 2014
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DOI | 10.1186/s13568-014-0068-1 |
Pubmed ID | |
Authors |
Narin Kirikyali, Jonathan Wood, Ian F Connerton |
Abstract |
β-xylosidases catalyse the hydrolysis of short chain xylooligosaccharides from their non-reducing ends into xylose. In this study we report the heterologous expression of Aspergillus oryzae β-xylosidase (XylA) in Pichia pastoris under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The recombinant enzyme was optimally active at 55°C and pH 4.5 with Km and Vmax values of 1.0 mM and 250 μmol min(-1) mg(-1) respectively against 4-nitrophenyl β-xylopyranoside. Xylose was a competitive inhibitor with a Ki of 2.72 mM, whereas fructose was an uncompetitive inhibitor reducing substrate binding affinity (Km) and conversion efficiency (Vmax). The enzyme was characterised to be an exo-cutting enzyme releasing xylose from the non-reducing ends of β-1,4 linked xylooligosaccharides (X2, X3 and X4). Catalytic conversion of X2, X3 and X4 decreased (Vmax and kcat) with increasing chain length. |
X Demographics
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Unknown | 1 | 100% |
Demographic breakdown
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Members of the public | 1 | 100% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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Unknown | 42 | 100% |
Demographic breakdown
Readers by professional status | Count | As % |
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Student > Ph. D. Student | 8 | 19% |
Student > Bachelor | 7 | 17% |
Researcher | 6 | 14% |
Student > Doctoral Student | 4 | 10% |
Student > Master | 4 | 10% |
Other | 7 | 17% |
Unknown | 6 | 14% |
Readers by discipline | Count | As % |
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Biochemistry, Genetics and Molecular Biology | 17 | 40% |
Agricultural and Biological Sciences | 11 | 26% |
Engineering | 2 | 5% |
Social Sciences | 1 | 2% |
Immunology and Microbiology | 1 | 2% |
Other | 2 | 5% |
Unknown | 8 | 19% |