Open AccessA novel carbohydrate:acceptor oxidoreductase from Microdochium nivale
Author(s) -
Xu Feng,
Golightly Elizabeth J.,
Fuglsang Claus C.,
Schneider Palle,
Duke Kyle R.,
Lam Loi,
Christensen Søren,
Brown Kimberly M.,
Jørgensen Christel T.,
Brown Stephen H.
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2001.01982.x
Subject(s) - oxidoreductase , biochemistry , chemistry , flavin group , isoelectric point , enzyme , electron acceptor , molecular mass , amino acid , stereochemistry
A Microdochium nivale carbohydrate:acceptor oxidoreductase was purified, cloned, heterologously expressed, and characterized. The gene encoding the protein showed one intron, and the ORF showed a sequence with low homology (≤ 25% identity or 65% similarity) to other known flavin‐containing carbohydrate oxidases. The maturation of the protein required the cleavage of a tetrameric propeptide in addition to an 18 amino‐acid signal peptide. The enzyme was found to have a relative molecular mass of 55 000 Da, an isoelectric point of 9, and one FAD per protein. It could oxidize mono‐, oligo‐, or polymeric saccharides, and transfer their electrons to O 2 or other acceptors. When d ‐glucose served as electron‐donating substrate, an activity of 2 s −1 was observed at pH 5.5 and 23 °C. Among various oligosaccharides, the enzyme preferred tetrameric dextrins, indicating a favorable interaction of four linked glucose units with the substrate pocket. The unique structure and ability of oxidizing oligo/polymeric saccharides suggest a promising prospect of this enzyme for various industrial/medicinal applications.