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Characterisation of a recombinant ?-xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris

Kirikyali, Narin; Wood, Jonathan; Connerton, Ian F.

Characterisation of a recombinant ?-xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris Thumbnail


Authors

Narin Kirikyali

Jonathan Wood

IAN CONNERTON IAN.CONNERTON@NOTTINGHAM.AC.UK
Northern Foods Professor of Food Safety



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.

Citation

Kirikyali, N., Wood, J., & Connerton, I. F. (2014). Characterisation of a recombinant ?-xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris. AMB Express, 4(68), https://doi.org/10.1186/s13568-014-0068-1

Journal Article Type Article
Publication Date Aug 31, 2014
Deposit Date May 22, 2015
Publicly Available Date May 22, 2015
Journal AMB Express
Electronic ISSN 2191-0855
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 4
Issue 68
DOI https://doi.org/10.1186/s13568-014-0068-1
Public URL https://nottingham-repository.worktribe.com/output/733589
Publisher URL http://www.amb-express.com/content/4/1/68

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