Glucose oxidase converted into a general sugar-oxidase

Area of Science:

• Biochemistry
• Enzyme Engineering
• Materials Science

Background:

• Glucose oxidase (GOx) is a widely used enzyme for D-glucose detection.
• Enzyme specificity often limits applications with other saccharides.
• Developing broader substrate specificity and enhanced stability is crucial for enzyme utility.

Purpose of the Study:

• To engineer a generalized saccharide oxidase from glucose oxidase.
• To investigate the effect of metallic gold entrapment on enzyme activity and stability.
• To explore the mechanism behind the broadened substrate specificity.

Main Methods:

• Entrapment of glucose oxidase (GOx) within a metallic gold matrix.
• Characterization of enzyme activity against a panel of different saccharides.
• Analysis of protein-gold interactions and conformational changes using spectroscopy.
• Assessment of thermal stability and reusability of the entrapped enzyme.

Main Results:

• Entrapped GOx exhibited oxidase activity towards fructose, xylose, L-glucose, glucose-6-phosphate, sucrose, lactose, methylglucoside, and raffinose.
• This generalized activity was observed for sugars lacking natural specific oxidases.
• Strong protein-gold and CTAB-gold/protein interactions were identified as key factors.
• Conformational changes in the GOx active site channel were proposed to increase substrate accessibility.
• The entrapped enzyme showed increased thermal stability up to 100 °C and allowed for convenient reuse.

Conclusions:

• Metallic gold entrapment successfully converted GOx into a general saccharide oxidase.
• The observed generalization of activity is attributed to specific interactions and induced conformational changes.
• The enhanced thermal stability and reusability of entrapped GOx offer significant practical advantages.