Subject index volume 144 |
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Authors: | Sudeep Kumar,Daniel Ramó n |
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Affiliation: | Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de Correos 73, 46100 Burjassot, Valencia, Spain |
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Abstract: | Abstract β-xylosidase (EC 3.2.1.37) has been purified from Aspergillus nidulans mycelium grown on oat-spelt xylan as sole carbon source. Its pH optimum for activity was found to be 5.0 and the optimum temperature was 50 °C. Its molecular mass was estimated by gel filtration to be 180000. Using p-nitrophenyl-β-d-xylopyranoside as substrate, the K m and V max values have been found to be 1.1 mM and 25.6 μmol min−1(mg protein)−1, respectively. Enzyme activity was inhibited by Hg2+, Ag2+, and Cu2+ at a concentration of 1 × 10−3 M. The synthesis of β-xylosidase in A. nidulans is strongly induced by arabinose and xylose and is subject to carbon catabolite repression mediated by the cre A gene product. |
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Keywords: | Aspergillus nidulans β-Xylosidase Purification Carbon catabolite repression CREA |
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