Enzymatic kinetic of cellulose hydrolysis : Inhibition by ethanol and cellobiose

The ethanol effect on the Trichoderma reesei cellulases was studied to quantify and clarify this inhibition type. To determine inhibition parameters of crude cellulase and purified exoglucanase Cel7A, integrated Michaelis-Menten equations were used assuming the presence of two inhibitors: cellobiose...

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Bibliographic Details
Published in:Applied biochemistry and biotechnology 2005-07, Vol.126 (1), p.49-59
Main Authors: BEZERRA, Rui M. F, DIAS, Albino A
Format: Article
Language:English
Subjects:
Biochemistry
Biological and medical sciences
Biotechnology
Cellobiose - chemistry
Cellulase - antagonists & inhibitors
Cellulase - chemistry
Cellulose
Cellulose - chemistry
Cellulose 1,4-beta-Cellobiosidase - chemistry
Combinatorial Chemistry Techniques
Computer Simulation
Enzyme Activation
Enzyme Inhibitors - chemistry
Enzymes
Ethanol
Ethanol - chemistry
Fermentation
Fundamental and applied biological sciences. Psychology
Fungi
Hydrolysis
Hypocrea jecorina
Inhibition
Kinetics
Models, Chemical
Studies
Trichoderma - enzymology
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Summary:The ethanol effect on the Trichoderma reesei cellulases was studied to quantify and clarify this inhibition type. To determine inhibition parameters of crude cellulase and purified exoglucanase Cel7A, integrated Michaelis-Menten equations were used assuming the presence of two inhibitors: cellobiose as the reaction product and ethanol as a possible bioproduct of cellulose fermentation. It was found that hydrolysis of cellulose by crude enzyme follows a model that considers noncompetitive inhibition by ethanol, whereas Cel7A is very slightly competitively inhibited. Crude cellulase is much more inhibited (K(iul) = K(icl) = 151.9 mM) than exoglucanase Cel7A (K(icl) = 1.6 x 1015 mM). Also, calculated inhibition constants showed that cellobiose inhibition is more potent than ethanol inhibition both for the crude enzyme as well as exoglucanase Cel7A.
ISSN:0273-2289
1559-0291
DOI:10.1007/s12010-005-0005-5