An overview of Glucose Oxidase (GOD)

Posted by beauty33 on June 26th, 2019

Glucose Oxidase (GOD) is an important industrial enzyme in the food industry. It is widely used in food, beer, juice, milk powder and other food deoxidation, flour improvement, food browning prevention, etc. And biosensors are also widely used. GOD is widely distributed in animals, plants and microorganisms. It is a major source of GOD production by the rapid growth and proliferation of microorganisms. The main production strains are Aspergillus niger and Penicillium.

Glucose oxidase (GOD), the system name is β-D-glucose oxidoreductase, has a wide range of applications, and its application potential has been the focus of many researchers. More and more are used in the food industry, textile bleaching and dyeing industries, etc., and are also widely used in emerging fields such as biofuels and glucose biosensors.

GOD can specifically catalyze the production of gluconic acid and hydrogen peroxide by β-D-glucose under aerobic conditions (Fig. 1). People are used to aerobic dehydrogenase, also known as oxidase, such as amine oxidase, jaundice. Oxidase and the like. GOD is widely distributed in animals, plants and microorganisms. Due to the rapid growth and proliferation of microorganisms and the wide source, it is the main source of GOD production. The main production strains are Aspergillus niger and Penicillium. At present, the application field of GOD continues to expand, and the demand in the domestic and international markets has increased dramatically. The low yield, low enzyme activity and complex detection method are the limiting factors for the industrialization of GOD. A lot of work has been done at home and abroad and significant progress has been made.

Antioxidant mechanism of GOD

GOD can consume molecular oxygen or atomic oxygen to oxidize glucose, protecting the easily oxidized components in food. According to the reaction conditions, there are three kinds of GOD catalytic reactions.
Type:

• 1 mol of oxygen per 1 mol of glucose consumed in the absence of catalase:

C6H12O6+O2→C6H12O7+H2O2;

β-D-glucose + O2→β-D-glucosaccharide + H2O2

• In the presence of catalase, 1/2 mol of oxygen per 1 mol of glucose consumed:

C6H12O6+1/2O2→C6H12O7+H2O2

• In the presence of ethanol and catalase, catalase can be used for the oxidation of ethanol, which consumes 1 mol of oxygen per 1 mol of glucose:

C6H12O6+ C2H5OH+O2→C6H12O7+ CH3CHO +H2O2

In addition, GOD exhibits strong specificity for β-D-glucose, and the hydroxyl group on the glucose molecule C (1) is essential for the catalytic activity of the enzyme, and the activity of the hydroxyl group at the β position is higher than that at the α position 160 times. Substrate C (2), C (3), C (4), C (5), to change the configuration of C (6) will greatly affect its enzymatic activity, but still partially retained enzymatic activity. Glucose oxidase is completely inactive against L-glucose and 2-O-methyl-D-glucose

Structure and enzymatic properties of GOD

Enzyme structure

GOD is a homodimeric molecule containing two flavin adenine dinucleotide (FAD) binding sites. Each monomer contains two completely different regions: one is non-covalent but tightly bound to part of the FAD, mainly β-sheet; the other is bound to the substrate β-D-glucose, and is supported by 4 α-helices. Parallel beta folding.

Enzymatic properties

The high-purity GOD is light yellow crystal, soluble in water, and can be made into a liquid preparation. GOD is completely insoluble in organic solvents such as ether, chloroform, butanol, pyridine, glycerin, and ethylene glycol. The relative molecular mass of GOD is generally around 1.5×105, and the enzyme per molecule contains 2 molecules of FAD. The pH range is from 3.5 to 6.5, and the optimum pH is about 5.0. It will be rapidly deactivated in the absence of a protective agent at pH > 8.0 or pH < 3.0. The temperature range of the GOD is generally 30 to 60 °C. The solid enzyme preparation can be stored for at least 2 years at 0 °C and 8 years at -15 °C.

About Author

Creative Enzymes is a US-based biotech company that has rich expertise in enzyme manufacturing, such as Catalase, Pectinase, Glucose Oxidase, for life science research and production of medicines, food, alcohol, beer, fruit juice, fabric, paper, leather goods, etc.