Purification and partial characterization [omicron]f a new [beta]-xylosidase from Humicola grisea var. thermoidea

The thermophilic fungus Humicola grisea var. thermoidea produces a mycelium-associated β-xylosidase activity when grown in liquid-state cultures on media containing oat spelt xylan as the carbon source. The β-xylosidase was purified to apparent homogeneity by gel filtration and anion exchange chroma...

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Bibliographic Details
Published in:World journal of microbiology & biotechnology 2006-05, Vol.22 (5), p.475
Main Authors: Iembo, T, Azevedo, Mo, Jr, C Bloch, Filho, Exf
Format: Article
Language:English
Subjects:
Anion exchange
Bacteria
Carbon sources
Enzymes
Mass spectrometry
Online Access:Get full text
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Summary:The thermophilic fungus Humicola grisea var. thermoidea produces a mycelium-associated β-xylosidase activity when grown in liquid-state cultures on media containing oat spelt xylan as the carbon source. The β-xylosidase was purified to apparent homogeneity by gel filtration and anion exchange chromatography. Its molecular weight was 37 and 50 kDa, as determined by MALDI/TOF mass spectrometry and SDS-PAGE, respectively. The purified enzyme exhibited maximum activity at 55 °C and pH 6.5. It was also active at pH 8.8, retaining 60% of its activity after 6 h of incubation at 50 °C. β-xylosidase was strongly inactivated by NBS and slightly activated by DTT and β-mercaptoethanol. The enzyme was highly specific for PNPX as the substrate. The purified β-xylosidase showed K ^sub m^ and V ^sub max^ values of 1.37 mM and 12.98 IU ml^sup -1^, respectively.[PUBLICATION ABSTRACT]
ISSN:0959-3993
1573-0972
DOI:10.1007/s11274-005-9059-3