Induction of extracellular arabinases on monomeric substrates in Aspergillus niger |
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Authors: | Peter v d Veen Michel J A Flipphi Alphons G J Voragen Jaap Visser |
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Institution: | (1) Department of Genetics, Section Molecular Genetics, Agricultural University, Dreyenlaan 2, 6703 HA Wageningen, The Netherlands;(2) Department of Food Science, Agricultural University, Dreyenlaan 2, 6703 HA Wageningen, The Netherlands |
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Abstract: | The induction of extracellular arabinases by pentose sugars and polyols generated by the metabolic pathway of l-arabinose and d-xylose catabolism in Aspergillus niger was investigated. Induction occurred with l-arabinose and l-arabitol but not with d-xylose or xylitol. l-arabitol in particular was found to be a good inducer for -l-arabinofuranosidase and endo-arabinase activities. Western blotting analysis showed both -l-arabinofuranosidase A and B to be present. No induction was observed using d-arabitol. Unlike the wild type A. niger N402 strain, the A. niger xylulose kinase negative mutant N572 also showed induction of -l-arabinofuranosidases A and B and endo-arabinase activity on d-xylose and xylitol. This is due to metabolic conversion of these compounds leading to the accumulation of both xylitol and l-arabitol in this mutant, the latter of which then acts as inducer. The induction of the two -l-arabinofuranosidases and endo-arabinase is under the control of two regulatory systems namely pathway specific induction and carbon catabolite repression. Under derepressing conditions in the wild type only -l-arabinofuranosidase B could be detected by Western blotting analysis. This indicates that -l-arabinofuranosidase B is of importance in the initiation of specific induction of the various arabinose activities in A. niger grown on arabinose containing structural polysaccharides.Abbreviations PNA
p-nitrophenyl--l-arabinofuranoside |
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Keywords: | Aspergillus niger Enzyme induction Arabinases -l-Arabinofuranosidases" target="_blank">gif" alt="agr" align="BASELINE" BORDER="0">-l-Arabinofuranosidases extracellular enzymes l-Arabitol induction" target="_blank">l-Arabitol induction |
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