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Gewählte Publikation:

Karapetyan, KN; Fedorova, TV; Vasil'chenko, LG; Ludwig, R; Haltrich, D; Rabinovich, ML.
(2006): Properties of neutral cellobiose dehydrogenase from the ascomycete Chaetomium sp. INBI 2-26(-) and comparison with basidiomycetous cellobiose dehydrogenases.
J Biotechnol. 2006; 121(1):34-48 FullText FullText_BOKU

The extracellular cellobiose dehydrogenase (CDH) obtained from Chaetomium sp. INBI 2-26(-) has a molecular mass of 95 kDa and an isoelectric point of 5. This novel CDH is highly specific for the oxidation of cellobiose (K-m,K-app 4.5 mu M) and lactose (K-m,K-app 56 mu M). With 2,6-dichloroindophenol (DOP) and cytochrome c(3+) (cyt c(3+)) as electron acceptors, CDH was most active at pH 6. The turnover number of the enzyme for cellobiose, lactose, DOP and cyt c(3+) was in the range of 9-14 s(-1) at 20 degrees C and pH 6. The UV-visible spectrum revealed the flavohemoprotein nature of the enzyme. The cytochrome b domain of the enzyme was reduced by ascorbate, dithionite, as well as specifically by cellobiose in a wide range of pH. The apparent first order rate constants of the spontaneous re-oxidation of the reduced heme domain were estimated as 0.01 and 0.00039 s(-1) at pH 4.5 and 6.5, respectively. The half-inactivation time of CDH at pH 6 and 55 degrees C was ca. 100 min; the stability at pH 8 and, particularly, pH 4 was remarkably lower. Cellobiose stabilized the enzyme against thermal inactivation, whereas DOP in turn sensitized the enzyme. The new enzyme revealed low affinity for crystalline cellulose, but was capable of binding onto H3PO4-swollen filter paper. The results show significant differences to already known CDHs and perspectives for several biotechnological applications, where CDH with maximal activity at neutral pH and high affinity for cellobiose and lactose night have some advantages. (c) 2005 Elsevier B.V. All rights reserved.
Autor/innen der BOKU Wien:
Haltrich Dietmar
Ludwig Roland
BOKU Gendermonitor:

Find related publications in this database (using NML MeSH Indexing)
2,6-Dichloroindophenol - chemistry
Basidiomycota - enzymology
Carbohydrate Dehydrogenases - analysis
Cellobiose - chemistry
Chaetomium - enzymology
Cytochrome c Group - chemistry
Enzyme Activation - chemistry
Fungal Proteins - analysis
Hot Temperature - analysis
Hydrogen-Ion Concentration - analysis
Lactose - chemistry
Oxidation-Reduction - chemistry
Substrate Specificity - chemistry

Find related publications in this database (Keywords)
cellobiose dehydrogenase
Chaetomium sp.
Sclerotium rolfsii
Phanerochaete chrysosporium
kinetic mechanism

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