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KMID : 0613820070170101341
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Journal of Life Science
2007 Volume.17 No. 10 p.1341 ~ p.1346
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Purification and Characterization of β-Xylosidase from Paenibacillus sp. DG-22
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Lee Tae-Hyeong
Lim Pyung-Ok
Lim Pyung-Ok
Lee Yong-Eok
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Abstract
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An intracellular β-xylosidase from Paenibacillus sp. DG-22 was purified to homogeneity by ion-exchange, hydrophobic interaction and gel-filtration chromatography. The molecular weight of the enzyme was measured to be 156,000 by gel filtration and 80,000 by SDS-PAGE, indicating that the enzyme consisted of two identical subunits. The purified enzyme exhibited maximum activity at 65℃ and pH 5.5. It retained 80% of its initial activity up to 60 min at 60℃ and had a half-life of 25 min at 65℃. The enzyme was highly specific for pNPX as the substrate. It showed little or no activity against other p-nitrophenyl glycosides and xylans. The Km and Vmax for pNPX was 0.53 mM and 3.18 U/mg protein, respectively. The β-xylosidase was strongly inhibited by Ag+, Fe2+, Hg2+ and Zn2+ and slightly activated by DTT. The hydrolysis product from xylobiose, xylotriose, and xylotetraose was xylose.
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KEYWORD
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Paenibacillus sp., β-xylosidase, purification
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