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Characterization of kinetics and thermostability of Acremonium strictum glucooligosaccharide oxidase
Author(s) -
Fan Zhiliang,
Oguntimein Gbekeloluwa B.,
Reilly Peter J.
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(20000420)68:2<231::aid-bit12>3.0.co;2-d
Subject(s) - thermostability , maltotriose , chemistry , maltose , enzyme kinetics , kinetics , substrate (aquarium) , oxidase test , enzyme , stereochemistry , biochemistry , active site , biology , ecology , physics , quantum mechanics
The kinetic and thermostability properties of a glucooligosaccharide oxidase from Acremonium strictum were determined. This enzyme produces only maltobionic acid from maltose. It is most active at pH 9 to 10.5, and is most stable at pH 6.5. Values of both K M and V max on maltose are highest at pH 10. The highest values of K M and V max occur with glucose, maltopentaose, and maltoheptaose, whereas the lowest values of K M are with maltotriose and of V max are with maltohexaose. Values of K M with any substrate and at any pH are always substantially above 1 m M . Activation energies for catalysis and thermoinactivation are 23 kJ/mol and 421 kJ/mol, respectively. The N‐terminal sequence is not homologous with any other oxidase, but has some homology with other proteins having different functions. These unusual properties suggest that glucooligosaccharides may not be the primary substrates of this enzyme. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 231–237, 2000.