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Purification and Characterization of a Glycoside Hydrolase Family 43 β-xylosidase from Geobacillus thermoleovorans IT-08
| Content Provider | Semantic Scholar |
|---|---|
| Author | Wagschal, Kurt C. Heng, Chamroeun Lee, Charles C. Robertson, George Heddle Dr Orts, William J. Wong, Dominic W. S. |
| Copyright Year | 2009 |
| Abstract | The gene encoding a glycoside hydrolase family 43 β-xylosidase (GbtXyl43A) from the thermophilic bacterium Geobacillus thermoleovorans strain IT-08 was synthesized and cloned with a C-terminal His-tag into a pET29b expression vector. The recombinant gene product termed GbtXyl43A was expressed in Escherichia coli and purified to apparent homogeneity. Michaelis–Menten kinetic parameters were obtained for the artificial substrates p-nitrophenyl-β-d-xylopyranose (4NPX) and p-nitrophenyl-α-l-arabinofuranose (4NPA), and it was found that the ratio kcat/Km 4NPA/kcat/Km 4NPX was ∼7, indicting greater catalytic efficiency for 4NP hydrolysis from the arabinofuranose aglycon moiety. Substrate inhibition was observed for the substrates 4-methylumbelliferyl xylopyranoside (muX) and the arabinofuranoside cogener (muA), and the ratio kcat/Km muA/kcat/Km muX was ∼5. The enzyme was competitively inhibited by monosaccharides, with an arabinose Ki of 6.8 ± 0.62 mM and xylose Ki of 76 ± 8.5 mM. The pH maxima was 5.0, and the enzyme was not thermally stable above 54 °C, with a t1/2 of 35 min at 57.5 °C. GbtXyl43A showed a broad substrate specificity for hydrolysis of xylooligosaccharides up to the highest degree of polymerization tested (xylopentaose), and also released xylose from birch and beechwood arabinoxylan. |
| Starting Page | 1 |
| Ending Page | 10 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1007/s12010-008-8362-5 |
| PubMed reference number | 18815904 |
| Journal | Medline |
| Volume Number | 155 |
| Alternate Webpage(s) | https://naldc.nal.usda.gov/naldc/download.xhtml?content=PDF&id=34750 |
| Alternate Webpage(s) | https://doi.org/10.1007/s12010-008-8362-5 |
| Journal | Applied biochemistry and biotechnology |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
