| Autor: |
Jari Vehmaanperä, Jarno Kallio, Christian Gamauf, Bernhard Seiboth, Christian P. Kubicek, Terhi Puranen, Martina Marchetti, Günter Allmaier |
| Rok vydání: |
2007 |
| Předmět: |
|
| Zdroj: |
FEBS Journal. 274:1691-1700 |
| ISSN: |
1742-464X |
| Popis: |
The extracellular bga1-encoded β-galactosidase of Hypocrea jecorina (Trichoderma reesei) was overexpressed under the pyruvat kinase (pki1) promoter region and purified to apparent homogeneity. The monomeric enzyme is a glycoprotein with a molecular mass of 118.8 ± 0.5 kDa (MALDI-MS) and an isoelectric point of 6.6. Bga1 is active with several disaccharides, e.g. lactose, lactulose and galactobiose, as well as with aryl- and alkyl-β-d-galactosides. Based on the catalytic efficiencies, lactitol and lactobionic acid are the poorest substrates and o-nitrophenyl-β-d-galactoside and lactulose are the best. The pH optimum for the hydrolysis of galactosides is ∼ 5.0, and the optimum temperature was found to be 60 °C. Bga1 is also capable of releasing d-galactose from β-galactans and is thus actually a galacto-β-d-galactanase. β-Galactosidase is inhibited by its reaction product d-galactose and the enzyme also shows a significant transferase activity which results in the formation of galacto-oligosaccharides. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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