Trehalose-mediated thermal stabilization of glucose oxidase from Aspergillus niger

• Published in: Journal of biotechnology Vol. 141; no. 3; pp. 130 - 136
• Main Authors: Paz-Alfaro, Karina J., Ruiz-Granados, Yadira G., Uribe-Carvajal, Salvador, Sampedro, José G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20.05.2009; [New York, NY]: Elsevier; Elsevier
• Subjects: Aspergillus niger; Aspergillus niger - enzymology; Biological and medical sciences; Biotechnology; Enzyme Stability; FAD dissociation; Flavin-Adenine Dinucleotide - metabolism; Fluorescence; Fundamental and applied biological sciences. Psychology; Glucose oxidase; Glucose Oxidase - isolation & purification; Glucose Oxidase - metabolism; Kinetics; Protein Folding; Spectrometry, Fluorescence; Temperature; Thermal inactivation; Trehalose; Trehalose - metabolism; Fluorescence; Glucose oxidase; FAD dissociation; Trehalose; Thermal inactivation; Fungi; Enzyme; Aspergillus niger; Thermal stabilization; Fungi Imperfecti; Oxidoreductases; Inactivation
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2009.03.002

Thermal inactivation and enzyme kinetics of glucose oxidase (a FAD dependent enzyme) were studied in the absence and presence of trehalose. The inactivation rate constant decreased by up to 50% at temperatures between 50 and 70 °C in the presence of 0.6 M trehalose; as a consequence the glucose oxidase half-life increased. Intrinsic fluorescence spectra showed a maximum center of spectral mass (CSM) red shift of 6.5 nm. Therefore, major structural changes seem to be related to glucose oxidase thermal inactivation. Trehalose decreased the rate constant for unfolding as monitored by CSM red shift kinetics indicating that this disaccharide favors the most compact folded state. The E a for unfolding was increased from 204 to 221 kJ mol −1. It is proposed that FAD dissociation is preceded by the exposition of hydrophobic regions, while the presence of trehalose was able to hinder the release of FAD. Enzyme kinetics analysis showed that trehalose does not affect V max but instead decreases K m; as a result enzyme efficiency was increased. The stabilizing effect of trehalose in a cofactor-dependent enzyme has not been tested to date. In addition, glucose oxidase has an enormous commercial importance and therefore, the use of trehalose to stabilize glucose oxidase in its multiple applications seems to be promising.