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Kirikyali, Narin and Wood, Jonathan and Connerton, Ian F. (2014) Characterisation of a recombinant β- xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kirikyali, Narin Wood, Jonathan Connerton, Ian F. |
| Copyright Year | 2016 |
| 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 mg 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. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://eprints.nottingham.ac.uk/28794/1/s13568-014-0068-1.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
