| Autor: |
de Vries, Ronald P., Pařenicová, Lucie, Hinz, Sandra W. A., Kester, Harry C. M., Beldman, Gerrit, Benen, Jacques A. E., Visser, Jaap |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; Oct2002, Vol. 269 Issue 20, p4985-4993, 9p |
| Abstrakt: |
The Aspergillus niger β-1,4-endogalactanase encoding gene (galA ) was cloned and characterized. The expression of galA in A. niger was only detected in the presence of sugar beet pectin, d-galacturonic acid and l-arabinose, suggesting that galA is coregulated with both the pectinolytic genes as well as the arabinanolytic genes. The corresponding enzyme, endogalactanase A (GALA), contains both active site residues identified previously for the Pseudomonas fluorescens β-1,4-endogalactanase. The galA gene was overexpressed to facilitate purification of GALA. The enzyme has a molecular mass of 48.5 kDa and a pH optimum between 4 and 4.5. Incubations of arabinogalactans of potato, onion and soy with GALA resulted initially in the release of d-galactotriose and d-galactotetraose, whereas prolonged incubation resulted in d-galactose and d-galactobiose, predominantly. MALDI-TOF analysis revealed the release of l-arabinose substituted d-galacto-oligosaccharides from soy arabinogalactan. This is the first report of the ability of a β-1,4-endogalactanase to release substituted d-galacto-oligosaccharides. GALA was not active towards d-galacto-oligosaccharides that were substituted with d-glucose at the reducing end. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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