Glucose Oxidase, Glucose Oxidoreductase, GOD, GOx, 9001-37-0

Glucose Oxidase, Glucose Oxidoreductase, GOD, GOx, 9001-37-0

GLUCOSE OXIDASE (GOD)

Glucose Oxidase / β-D-Glucose Oxidoreductase / GOD / GOx

• CAS Number: 9001-37-0

• EC Number: 232-601-0

• Enzyme Class: EC 1.1.3.4

SECTION 1: PRODUCT DEFINITION AND CHEMICAL IDENTITY

Description:
Glucose Oxidase is an oxidoreductase enzyme that oxidizes glucose to produce hydrogen peroxide (H₂O₂) and gluconic acid. As a flavoprotein, the enzyme contains FAD (Flavin Adenine Dinucleotide) as a cofactor. During the reaction, molecular oxygen (O₂) is used as the electron acceptor, producing hydrogen peroxide. In the food industry, it is used as a preservative; through oxygen consumption and hydrogen peroxide production, it limits microbial growth. It is used especially in dairy products (cheese, yogurt), bakery products (bread, cakes), beverages (fruit juice, beer), and egg products for stability, shelf-life extension, and preservation. It is also used in biosensors, glucose determination, and industrial biocatalysis.

SECTION 2: SYNONYMS AND OTHER NAMES

SECTION 3: ENZYMATIC STRUCTURE

3.1. Molecular Structure
Glucose Oxidase is a flavoprotein consisting of two identical subunits (homodimer). Each subunit contains one FAD (Flavin Adenine Dinucleotide) molecule bound by non-covalent bonds. The enzyme's active site is organized around the FAD molecule. FAD plays a critical role in the catalytic mechanism as an electron carrier. Aspergillus niger glucose oxidase typically has a molecular weight of ~80,000 Da and is highly glycosylated (carbohydrate content 10-20%).

3.2. Catalytic Mechanism
Glucose Oxidase catalyzes the conversion of glucose to gluconic acid and hydrogen peroxide in two main steps:

1. First Step (Oxidation): β-D-Glucose reacts with FAD (Flavin Adenine Dinucleotide) in the enzyme's active site. Glucose is oxidized to glucono-δ-lactone, and FAD is reduced to FADH₂.

2. Second Step (Reoxidation): The reduced FADH₂ is reoxidized by molecular oxygen (O₂). This reaction regenerates FAD and releases hydrogen peroxide (H₂O₂).

3. Lactone Hydrolysis: Glucono-δ-lactone is spontaneously or enzymatically hydrolyzed to gluconic acid with water.

3.3. Molecular Weight
60,000 - 80,000 Da (depending on source; Aspergillus niger: ~80,000 Da homodimer)

3.4. Basic Structural Properties

SECTION 4: PHYSICAL AND CHEMICAL PROPERTIES

SECTION 5: ENZYMATIC ACTIVITY AND REACTION

SECTION 6: REACTION MECHANISM

Glucose Oxidase catalyzes the conversion of glucose to gluconic acid and hydrogen peroxide through a mechanism involving the following steps:

6.1. Substrate Binding
The β-D-Glucose molecule binds to the enzyme's active site. Binding occurs through interactions between the C1 hydroxyl group of glucose and FAD.

6.2. Oxidation (First Half-Reaction)
The bound glucose is oxidized by FAD (Flavin Adenine Dinucleotide) in the enzyme. Glucose is converted to glucono-δ-lactone, and FAD is reduced to FADH₂. In this step, two hydrogen atoms are removed from glucose.

6.3. Lactone Hydrolysis
Glucono-δ-lactone is spontaneously or enzymatically hydrolyzed to gluconic acid with water. This step can occur in the enzyme's active site or in solution.

6.4. Reoxidation (Second Half-Reaction)
The reduced FADH₂ is reoxidized by molecular oxygen (O₂). This reaction regenerates FAD and releases hydrogen peroxide (H₂O₂). O₂ serves as the electron acceptor.

6.5. Overall Reaction
β-D-Glucose + O₂ + H₂O → Gluconic Acid + H₂O₂

SECTION 7: REACTION EQUATIONS

7.1. Glucose Oxidase Reaction (Main Reaction)
β-D-Glucose + O₂ + H₂O → Gluconic Acid + H₂O₂

7.2. First Half-Reaction (Oxidation)
β-D-Glucose + FAD → Glucono-δ-lactone + FADH₂

7.3. Second Half-Reaction (Reoxidation)
FADH₂ + O₂ → FAD + H₂O₂

7.4. Lactone Hydrolysis
Glucono-δ-lactone + H₂O → Gluconic Acid

7.5. Overall Reaction
β-D-Glucose + O₂ + H₂O → Gluconic Acid + H₂O₂

7.6. With Catalase (H₂O₂ Removal)
H₂O₂ → H₂O + ½ O₂ (with Catalase)

7.7. Enzyme Inactivation (Thermal)
Glucose Oxidase (active) → Glucose Oxidase (inactive) (≥50°C, 10-15 minutes)

SECTION 8: GLUCOSE OXIDASE TYPES

SECTION 9: APPLICATIONS AND INDUSTRIAL USES

9.1. Food Preservation

Example Recipe – Bread Preservation:

• Flour: 100 kg

• Glucose Oxidase: 10-100 g (depending on activity)

• Glucose: 0.5-1 kg

• Application temperature: Room temperature

• pH: 5.5-6.0

Mix glucose oxidase with flour. Dissolve glucose in dough water. Add enzyme and glucose during dough preparation. The enzyme oxidizes glucose, producing H₂O₂ and consuming O₂. This limits mold and yeast growth.

9.2. Dairy Products Industry

9.3. Bakery and Cereal Industry

9.4. Beverage Industry

9.5. Egg and Egg Products

9.6. Biosensor and Analytical Applications

9.7. Biocatalysis and Industrial Applications

SECTION 10: ALTERNATIVES AND COMPARISON

10.1. Glucose Oxidase vs Catalase

10.2. Glucose Oxidase vs Chemical Preservatives (Sorbate, Benzoate)

10.3. Glucose Oxidase vs Laccase (EC 1.10.3.2)

10.4. Glucose Oxidase vs Glucose Dehydrogenase (EC 1.1.1.47)

SECTION 11: TOXICOLOGY AND SAFETY

11.1. Acute Toxicity

11.2. Regulatory Status

SECTION 12: GHS CLASSIFICATION (Powder Form)

Signal Word: Danger

Hazard Pictograms: GHS07 (Exclamation mark), GHS08 (Health Hazard)

Hazard Statements (H-Codes):

• H334: May cause allergy or asthma symptoms if inhaled

• H319: Causes serious eye irritation

• H335: May cause respiratory irritation

Safety Statements (Historical):

SECTION 13: PRECAUTIONARY STATEMENTS (P-CODES)

SECTION 14: FIRST AID MEASURES

SECTION 15: FIREFIGHTING MEASURES

SECTION 16: ACCIDENTAL RELEASE MEASURES

SECTION 17: STORAGE AND SHELF LIFE

SECTION 18: PACKAGING OPTIONS

SECTION 19: TRANSPORT INFORMATION

SECTION 20: ENVIRONMENTAL INFORMATION

SECTION 21: REGULATORY STATUS

SECTION 22: FREQUENTLY ASKED QUESTIONS (FAQ)

Q1: Is glucose oxidase safe for food applications?
A1: Yes. Glucose Oxidase is classified as GRAS (Generally Recognized As Safe) by the FDA and approved as a food enzyme by EFSA. It is widely used in bread, cheese, yogurt, fruit juice, and beer. However, the powder form may cause allergic reactions when inhaled, so appropriate personal protective equipment should be used.

Q2: What is the role of glucose oxidase in food preservation?
A2: Glucose Oxidase oxidizes glucose to produce hydrogen peroxide (H₂O₂) and consume oxygen. H₂O₂ has antimicrobial effects and limits the growth of mold, yeast, and some bacteria. Oxygen consumption prevents oxidation (color, flavor, vitamin loss) in products. These two mechanisms extend shelf life and maintain product quality.

Q3: In which food products is glucose oxidase used?
A3: Glucose Oxidase is primarily used in: bread, cakes, biscuits (bakery); cheese, yogurt (dairy); fruit juice, beer, wine (beverages); egg white and egg powder (egg products). It can also be used in mayonnaise, salad dressings, and processed meat products.

Q4: Is glucose oxidase suitable for vegan and halal products?
A4: Microbial (fungal or bacterial) sourced glucose oxidases are suitable for vegan and halal certification. Since the product is produced from microorganisms such as Aspergillus niger or Penicillium, it contains no animal ingredients. Relevant certificates can be obtained from manufacturers.

Q5: What is the shelf life of glucose oxidase?
A5: In unopened original packaging, stored in a cool (4-25°C) and dry place away from direct sunlight, a shelf life of 12-24 months is recommended. For long-term storage, storing at 4°C minimizes activity loss. Contains FAD; light-sensitive; store in the dark.

Q6: How should glucose oxidase be stored?
A6: Store in a cool (preferably 4-25°C), dry, well-ventilated area in tightly closed, light-proof containers. Moisture, high temperature (>40°C), and direct sunlight cause activity loss. Contact with heavy metals (silver, copper, mercury) should be avoided.

Q7: What are the optimum working conditions for glucose oxidase?
A7: The optimum pH of glucose oxidase is between 5.0-6.0, and the optimum temperature varies between 30-40°C depending on the source. The enzyme is stable up to 40°C and rapidly inactivated above 50°C. It requires β-D-glucose as substrate and molecular oxygen (O₂) as electron acceptor. Substrate inhibition may occur at high glucose concentrations.

Q8: Why is glucose oxidase used in bread production?
A8: In bread production, glucose oxidase oxidizes glucose in the dough, producing H₂O₂ and consuming O₂. H₂O₂ strengthens the gluten network, increasing dough stability and volume. O₂ consumption prevents oxidation, maintaining bread color and flavor. Additionally, H₂O₂ limits mold and yeast growth, extending bread shelf life.

Q9: How is glucose oxidase used in biosensors?
A9: Glucose Oxidase is the key component of glucose biosensors. In biosensors, the enzyme oxidizes glucose, producing H₂O₂. The produced H₂O₂ is detected electrochemically or optically, generating a signal proportional to glucose concentration. This principle is used in blood glucose monitoring devices (diabetes diagnosis) and food analysis.

Q10: What are the effects of inhaling glucose oxidase powder?
A10: Glucose Oxidase powder, when inhaled, can cause allergic reactions, asthma-like symptoms, and respiratory tract irritation. Occupational asthma can develop upon repeated exposure to enzyme dust in food processing industries. Therefore, a dust mask (P2/P3) must always be used when handling the powder form, and local exhaust ventilation should be provided.

SECTION 23: QUICK REFERENCE TABLE

SECTION 24: CRITICAL WARNINGS AND BEST PRACTICES

CRITICAL WARNINGS:

1. Dust Control and Respiratory Sensitization: Glucose Oxidase powder can cause occupational asthma upon repeated exposure. Use local exhaust ventilation to prevent dust dispersion and always wear a dust mask (P2/P3). Liquid formulations are safer than powder forms.

2. Oxygen Requirement: Glucose Oxidase requires molecular oxygen (O₂) as electron acceptor. The enzyme does not work under anaerobic conditions. Ensure sufficient oxygen presence in applications. Oxygen presence is critical for the enzyme's preservative effect.

3. Substrate Inhibition: Glucose Oxidase shows substrate inhibition at high glucose concentrations (>100 mM). Optimum glucose concentration is in the range of 10-50 mM. Excessively high glucose concentrations reduce enzyme activity.

4. Activity Loss - Temperature: Glucose Oxidase is rapidly and irreversibly inactivated above 50°C. Strictly maintain application temperatures within the optimum range (30-40°C). Temperature control is critical in food processing and pasteurization.

5. Activity Loss - pH: Glucose Oxidase loses stability below pH 4.0 or above pH 7.0. Maintain application pH within the optimum range (5.0-6.0). Excessively acidic or basic conditions cause permanent enzyme inactivation.

6. H₂O₂ Production: Glucose Oxidase produces H₂O₂. High H₂O₂ concentrations can cause oxidative damage and undesirable flavor changes in products. Use with catalase to control H₂O₂ levels.

7. Activity Loss - Inhibitors: Heavy metals (Ag⁺, Hg²⁺, Cu²⁺), SDS, cyanide (CN⁻), and hydroxylamine inhibit glucose oxidase. Avoid these substances in equipment that comes into contact with the enzyme. Stainless steel, HDPE, or glass materials are preferred.

8. Food Grade: Only FDA/EFSA-approved food-grade glucose oxidase meeting specifications should be used in food applications. Industrial grade enzymes may contain impurities and are not suitable for human consumption.

BEST PRACTICE RECOMMENDATIONS:

• Storage: Store in a cool (4-25°C), dry, well-ventilated area in tightly closed, light-proof containers. For long-term storage, +4°C (refrigeration) is recommended. Use within a short period after opening.

• Handling: Use protective gloves, dust mask (P2/P3), and protective goggles. To prevent dust dispersion, preferably use liquid formulations. Prepare working solutions fresh for each application.

• Substrate Preparation: Maintain glucose concentration at optimum levels (10-50 mM). Add glucose if necessary. Ensure substrate concentration is not too high.

• Oxygen Supply: Provide sufficient aeration or oxygen to meet the enzyme's O₂ requirement. Monitor O₂ levels in closed systems.

• Dosage: Calculate the correct dosage according to enzyme activity. Check enzyme activity for each batch. Start with low dosage and adjust based on results. Typical dosage ranges are 5-100 ppm for bakery products and 0.001-0.005% for dairy products and beverages.

• Combination with Catalase: Use with catalase to control H₂O₂ levels. Catalase decomposes H₂O₂ into water and oxygen.

• Enzyme Inactivation: Inactivate the enzyme by heat treatment (≥50°C, 10-15 minutes) if necessary. In food products, pasteurization or cooking processes will inactivate the enzyme.

• Quality Control: Perform activity testing for each batch. Maintain production and handling hygiene to prevent microbiological contamination. Monitor preservative efficacy and oxygen consumption for consistent product quality.

• Waste Management: Dispose of enzyme and contaminated materials in accordance with local regulations. Do not discharge into sewers. If released into wastewater, inactivate the enzyme by heat treatment before disposal.

LEGAL DISCLAIMER:

This Technical Data Sheet (TDS) is for informational purposes only and is prepared based on available technical data. The user is responsible for determining the suitability of the product for their specific application and for complying with all local, national, and international regulations. For complete safety, storage, handling, transport, waste, and regulatory compliance information, refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Glucose Oxidase powder may cause sensitization when inhaled; appropriate protective equipment should be used. This document does not replace professional or medical advice.