Comparison of Enzymatic Glucose Detection Methods: Glucose Oxidase, Glucose Dehydrogenase, and Hexokinase Methods
Comparison of Enzymatic Glucose Detection Methods: Glucose Oxidase, Glucose Dehydrogenase, and Hexokinase Methods
The glucose oxidase method, glucose dehydrogenase method, and hexokinase method can all be used for glucose quantification, but they differ markedly in reaction principle, readout mode, interference profile, and platform compatibility. Method selection should be based on sample type, detection throughput, instrument conditions, and accuracy requirements.
Keywords: glucose detection; glucose oxidase method; glucose dehydrogenase method; hexokinase method; enzyme-coupled reaction; blood glucose detection; colorimetric method; NADPH
1 Technical Logic of Enzymatic Glucose Detection
1.1 Core Advantages of Enzymatic Detection
(1) High substrate selectivity
Enzymatic glucose detection uses the selective recognition of D-glucose by enzymes to convert glucose concentration into hydrogen peroxide, reduced coenzyme, electron transfer signal, or coupled product signal. Compared with nonspecific reducing sugar assays, enzymatic methods are more targeted toward glucose itself and are therefore more suitable for blood, cell culture medium, and complex biological samples.
(2) Flexible readout modes
The glucose oxidase method commonly uses peroxidase-coupled color development or electrochemical detection; the glucose dehydrogenase method can be read through NADH/NADPH absorbance, electrochemical mediators, or cofactor reduction signals; the hexokinase method usually generates NADPH through G6PDH coupling and quantifies glucose at 340 nm. Different readout modes determine method sensitivity, interference resistance, and platform compatibility.
(3) Clear differences in applicable scenarios
The glucose oxidase method is suitable for routine colorimetric detection, microplate assays, and general laboratory samples. The glucose dehydrogenase method is commonly used in glucometers, electrochemical biosensors, and some automated detection systems. The hexokinase method has relatively high stability and accuracy and is commonly used in clinical biochemical analysis and high-confidence quantitative testing.
1.2 Basic Division of the Three Methods
(1) Glucose oxidase method
Glucose oxidase (GOD/GOx) catalyzes the oxidation of β-D-glucose to glucono-δ-lactone and hydrogen peroxide. Hydrogen peroxide is then catalyzed by peroxidase and reacts with 4-aminoantipyrine, phenolic compounds, or other chromogenic substrates to form colored products. This method is simple to operate, relatively low-cost, and suitable for batch testing, but it is sensitive to oxygen, reducing interferents, and hydrogen peroxide scavengers.
(2) Glucose dehydrogenase method
Glucose dehydrogenase (GDH) catalyzes glucose oxidation while reducing NAD⁺, NADP⁺, PQQ, FAD, or other electron acceptors. This class of methods does not depend on oxygen and is suitable for electrochemical detection and portable blood glucose testing. However, substrate specificity and interference risks differ among different cofactor systems.
(3) Hexokinase method
Hexokinase (HK) catalyzes the conversion of glucose to glucose-6-phosphate in the presence of ATP. Subsequently, glucose-6-phosphate dehydrogenase (G6PDH) oxidizes glucose-6-phosphate to 6-phosphoglucono-δ-lactone while reducing NADP⁺ to NADPH. The increase in NADPH absorbance at 340 nm is related to glucose concentration. This method has high specificity and accuracy and is suitable for clinical biochemistry and high-quality quantitative analysis.
Table 1 Comparison of enzymatic glucose detection methods
Method | Core enzymes | Signal source | Common readout | Main advantages | Main limitations |
Glucose oxidase method | Glucose oxidase, peroxidase | H₂O₂-coupled colorimetric or electrochemical signal | 505 nm, 520 nm, 550 nm, or electrochemical detection | Low cost, simple operation, suitable for microplate and routine colorimetric assays | Affected by oxygen, reducing substances, and hydrogen peroxide scavengers |
Glucose dehydrogenase method | GDH-NAD, GDH-NADP, GDH-PQQ, GDH-FAD | Cofactor reduction or electron transfer | 340 nm, electrochemical detection | Oxygen-independent, suitable for sensors and rapid detection | Different GDH systems differ in cofactor and substrate interference |
Hexokinase method | Hexokinase, G6PDH | NADPH generation | 340 nm | High accuracy and specificity, suitable for clinical biochemistry | More complex reagent system; requires ATP, Mg²⁺, and stable enzyme activity |
Non-enzymatic reducing sugar method | No specific enzyme | Reducing reaction | Colorimetric detection | Low cost | Poor specificity; not suitable for accurate glucose quantification in complex biological samples |
2 Glucose Oxidase Method
2.1 Reaction Principle
(1) Glucose oxidation reaction
Glucose oxidase specifically catalyzes the oxidation of β-D-glucose to D-glucono-δ-lactone and H₂O₂. Glucono-δ-lactone can be further hydrolyzed to gluconic acid. This reaction uses oxygen as the electron acceptor; therefore, dissolved oxygen in the system affects reaction rate and linear range.
(2) Peroxidase-coupled color development
In colorimetric assays, H₂O₂ is usually used by horseradish peroxidase or other peroxidases to catalyze the oxidation of chromogenic substrates, generating measurable colored products. Common color development systems include 4-aminoantipyrine combined with phenolic compounds, TOOS, DAOS, ADPS, and other coupled substrates. Different substrates affect detection wavelength, sensitivity, and background value.
(3) Relationship between signal and glucose concentration
When enzyme amount, oxygen, chromogenic substrates, and reaction time are sufficient, the colored product generated is proportional to the glucose concentration in the sample. If sample glucose concentration is too high, oxygen is insufficient, or the color development system is depleted, linearity deteriorates, and sample dilution or reaction condition optimization is required.
2.2 Applicable Scenarios
(1) Routine blood glucose and tissue homogenate detection
The glucose oxidase method is suitable for detecting glucose in serum, plasma, tissue homogenate, and urine, especially for routine laboratory batch testing using a microplate reader or spectrophotometer. For blood samples, interference from hemolysis, bilirubin, ascorbic acid, and uric acid should be considered.
(2) Glucose consumption assays in cell culture medium
Cell culture medium generally contains relatively high glucose levels, and the glucose oxidase method can be used to evaluate cellular glucose consumption capacity. Culture time, cell number, medium volume, and cell viability should be recorded, and the results should be normalized to cell number or protein content.
(3) Food, fermentation broth, and bioprocess monitoring
In fermentation or food samples, the glucose oxidase method can be used for rapid glucose quantification. However, samples may contain reducing substances, pigments, polyphenols, ethanol, or other reactive components. Method compatibility should be verified by blank correction, sample dilution, and standard addition recovery tests.
2.3 Interfering Factors and Optimization
(1) Oxygen dependence
The glucose oxidase method depends on oxygen as the electron acceptor. In high-glucose or high-viscosity samples, dissolved oxygen may become a limiting factor, causing incomplete reaction. For high-glucose samples, dilution should be prioritized to keep the result within the linear range.
(2) Reducing interferents
Ascorbic acid, uric acid, glutathione, certain phenolic compounds, and reducing drugs can consume H₂O₂ or reduce chromogenic intermediates, leading to underestimated results. If samples are rich in reducing substances, an interference-resistant color development system, sample blank, or hexokinase method verification should be considered.
(3) Sample color and turbidity
Hemolysis, lipemia, bilirubin, food pigments, and tissue homogenate turbidity can affect colorimetric readings. For obviously colored or turbid samples, a sample background well should be included, or an endpoint method with blank subtraction should be used. When interference is severe, a more compatible detection system may be needed.
3 Glucose Dehydrogenase Method
3.1 Reaction System Types
(1) NAD/NADP-dependent GDH
NAD⁺- or NADP⁺-dependent GDH catalyzes glucose oxidation while generating NADH or NADPH, which can be detected by absorbance change at 340 nm. This system is oxygen-independent and is suitable for samples sensitive to oxygen concentration or when H₂O₂ interference needs to be avoided.
(2) PQQ-dependent GDH
PQQ-GDH has strong electrochemical compatibility and has been widely used in some blood glucose detection systems. Its limitation is the risk of cross-reactivity with some non-glucose sugars, especially in the presence of maltose, galactose, or xylose. In clinical samples with potential sugar interference, selection should be cautious.
(3) FAD-dependent GDH
FAD-GDH is commonly used in electrochemical glucose sensors. Its substrate selectivity is generally better than some PQQ-GDH systems, and it is oxygen-independent. This system is suitable for portable detection, electrode sensing, and continuous monitoring technologies, but specificity still needs to be confirmed based on enzyme source, mediator, and sensor design.
3.2 Method Advantages
(1) Oxygen independence
Unlike the glucose oxidase method, the GDH method does not use oxygen as the main electron acceptor, making it more stable in low-oxygen, high-viscosity, or sealed detection environments. This feature makes it more suitable for electrochemical blood glucose detection, sensors, and rapid detection with small sample volumes.
(2) Compatibility with electrochemical platforms
GDH can be combined with electron mediators or electrode systems to convert glucose concentration into current signals. This readout is rapid, requires small sample volumes, and is portable, making it an important basis for glucometers and some biosensors.
(3) Avoidance of H₂O₂ colorimetric system interference
The GDH-NAD(P) system does not rely on H₂O₂ or peroxidase-coupled color development, thereby reducing direct interference from ascorbic acid, uric acid, and similar substances in hydrogen peroxide-based systems. However, if electrochemical mediator detection is used, interference from electroactive substances still needs to be considered.
3.3 Application Limitations
(1) Substrate cross-reactivity
The substrate specificity of GDH systems is closely related to enzyme source and cofactor type. Some PQQ-GDH systems can cross-react with sugars such as maltose, causing overestimated glucose results. In sugar-containing infusion-related samples, dialysis-related samples, food samples, or complex carbohydrate matrices, substrate specificity should be verified first.
(2) Cofactor stability
NAD(P)-dependent systems require a stable cofactor supply. NADH/NADPH are sensitive to light, oxidation, and pH conditions, so storage and reaction conditions must be controlled. If the 340 nm background is high or the sample contains strongly absorbing substances, quantification can also be affected.
(3) Electrochemical interference
In electrochemical GDH detection, ascorbic acid, uric acid, acetaminophen, and other electroactive substances may affect current signals. Sensor systems usually reduce interference through membrane layers, mediators, and potential control, but performance must be verified for each platform.
4 Hexokinase Method
4.1 Reaction Principle
(1) Hexokinase-catalyzed phosphorylation
Hexokinase phosphorylates glucose to glucose-6-phosphate in the presence of ATP and Mg²⁺. This step converts glucose into a substrate that can be recognized by G6PDH and is the first reaction in the method.
(2) G6PDH-coupled NADPH generation
Glucose-6-phosphate is oxidized by G6PDH while NADP⁺ is reduced to NADPH. NADPH has characteristic absorbance at 340 nm, and the increase in absorbance is proportional to glucose content in the sample. This dual-enzyme coupling improves selectivity and accuracy.
(3) Stable reaction endpoint
The hexokinase method usually uses an endpoint or rate method, and the endpoint signal is relatively stable. As long as ATP, Mg²⁺, NADP⁺, HK, and G6PDH are sufficient, the target glucose can be converted more completely, making the method suitable for automated biochemical analyzers and standardized detection.
4.2 Method Advantages
(1) High accuracy
The hexokinase method is often regarded as one of the high-confidence methods for glucose quantification. Its detection signal comes from NADPH rather than an H₂O₂ colorimetric product, so it is less affected by hydrogen peroxide scavengers or color development system interference.
(2) Suitability for clinical biochemical platforms
The hexokinase method is suitable for automated detection of serum, plasma, cerebrospinal fluid, and other samples, with good repeatability and methodological consistency. For experiments requiring comparison with clinical data, long-term animal model data, or multicenter data, this method has clear advantages.
(3) Suitable for verification in complex interference backgrounds
When glucose oxidase results are suspected to be affected by reducing substances, pigments, or peroxidase system interference, the hexokinase method can be used as a verification method. For samples with strong reducing backgrounds or complex matrices, the HK method is generally more robust than H₂O₂ colorimetric systems.
4.3 Method Limitations
(1) More complex reagent system
The hexokinase method requires multiple components, including HK, G6PDH, ATP, Mg²⁺, and NADP⁺. Its reagent cost and formulation stability requirements are higher than those of the glucose oxidase method. When preparing the system in-house, enzyme activity, coenzyme stability, and buffer pH should be carefully controlled.
(2) Requirement for 340 nm detection
NADPH readout is usually performed at 340 nm and requires UV detection capability. Ordinary visible-light microplate readers that do not support 340 nm cannot directly use this method. If samples have strong absorbance background at 340 nm, blank correction is required.
(3) ATP consumption and reaction completeness
Insufficient ATP or Mg²⁺ affects the glucose phosphorylation step and causes underestimated results. For high-glucose samples, the reagent amount must be sufficient, and sample dilution may be needed to keep the concentration within the linear range.
5 Method Selection Strategy
5.1 Selection Based on Detection Purpose
(1) Routine glucose content detection
If the sample matrix is relatively simple, interferents are limited, and the laboratory platform mainly uses a visible-light microplate reader or spectrophotometer, the glucose oxidase method is usually a more economical and high-throughput option. Cell culture medium, tissue homogenate, and routine serum samples can all be tested using this method, but linear range and recovery should be verified.
(2) Rapid detection and sensor applications
If the goal is glucometer testing, continuous glucose monitoring, electrode sensing, or rapid readout using small sample volumes, the glucose dehydrogenase method is more common. GDH-FAD or optimized GDH systems can reduce oxygen dependence, but sugar cross-reactivity and interference from electroactive substances still need attention.
(3) Clinical-grade accuracy and method verification
If high accuracy, standardized clinical testing, or verification of other methods is required, the hexokinase method is more suitable. This method is insensitive to H₂O₂ colorimetric interference and is suitable for precise quantification of serum, plasma, and some complex biological samples.
5.2 Selection Based on Sample Type
(1) Serum and plasma
Common interferences in serum and plasma include hemolysis, lipemia, bilirubin, uric acid, and ascorbic acid. Routine testing can use the glucose oxidase method. If the sample interference is obvious or high accuracy is required, the hexokinase method should be selected. Glucometer-related platforms often use GDH or GOx electrochemical systems.
(2) Cell culture medium
Cell culture medium generally contains high glucose concentrations, and both the glucose oxidase method and hexokinase method can be used. If the medium contains phenol red, ascorbic acid, reducing agents, or color background, a medium blank should be included. When comparing glucose consumption among treatment groups, results should be normalized to cell number, protein content, or cell viability.
(3) Tissue homogenate
Tissue homogenates contain proteins, pigments, reducing substances, and endogenous enzymes, which can easily affect colorimetric systems. For the glucose oxidase method, a sample blank and recovery validation should be included. In liver, muscle, and brain tissues with complex backgrounds, the hexokinase method or sample pretreatment can be considered.
(4) Food and fermentation samples
Food and fermentation broth may contain multiple sugars, pigments, polyphenols, organic acids, and microbial metabolites. The GOx method is suitable when glucose is the main target and interference from non-glucose sugars is limited. The GDH method requires attention to sugar cross-reactivity. For complex systems, accuracy should be verified using the standard addition method.
Table 2 Selection of glucose detection methods for different sample types
Sample type | Recommended primary method | Alternative method | Main considerations |
Routine serum/plasma | Hexokinase method, glucose oxidase method | GDH electrochemical method | Hemolysis, lipemia, bilirubin, uric acid, ascorbic acid |
Animal blood glucose model | Glucose oxidase method, hexokinase method | GDH method | Fasting time, blood collection stress, sample volume |
Cell culture medium | Glucose oxidase method | Hexokinase method | Phenol red, medium background, normalization to cell number |
Tissue homogenate | Hexokinase method | Glucose oxidase method | Pigments, turbidity, endogenous reducing substances |
Urine | Glucose oxidase method | Hexokinase method | Uric acid, ascorbic acid, dilution factor |
Food samples | Glucose oxidase method | HK method, GDH method | Pigments, polyphenols, non-glucose sugars |
Fermentation broth | Glucose oxidase method, GDH method | HK method | Ethanol, organic acids, pigments, cell turbidity |
Sensor/POCT | GDH-FAD, GDH-PQQ, GOx electrochemical method | Not applicable | Electrochemical interference, oxygen dependence, sugar cross-reactivity |
6 Interfering Factors and Result Interpretation
6.1 Common Abnormal Results in the Glucose Oxidase Method
(1) Low results
Low results commonly occur due to insufficient oxygen, hydrogen peroxide scavenging by reducing substances, insufficient chromogenic substrate, or decreased enzyme activity. Samples containing ascorbic acid, uric acid, glutathione, bilirubin, or polyphenols should be carefully evaluated for false-low risk.
(2) High results
Deep sample background color, high turbidity, or insufficient blank subtraction can lead to high results. Substances that directly participate in the color development reaction or affect the peroxidase system may also cause abnormally high readings.
(3) Loss of linearity
If high-glucose samples are not diluted, oxygen, substrate, or the chromogenic system may become limiting, causing nonlinearity. The standard curve should cover the sample concentration range, and samples above the range must be diluted and retested.
6.2 Common Abnormal Results in the Glucose Dehydrogenase Method
(1) Cross-reactivity with non-glucose sugars
Some GDH systems may respond to sugars such as maltose, galactose, or xylose, causing overestimated results. In complex food samples, sugar-containing infusion-related samples, or special treatment contexts, the GDH enzyme type and cofactor system should be confirmed.
(2) Electroactive substance interference
In electrochemical detection, ascorbic acid, uric acid, acetaminophen, and other substances may affect current signals. Different sensors reduce interference through membrane layers, potential control, and mediator optimization, but methodological validation remains necessary.
(3) Instability of cofactors or mediators
NAD(P) systems are sensitive to cofactor stability, while electrochemical systems depend on mediator and electrode status. Long-term reagent storage, repeated freeze-thaw, or electrode batch differences may all cause result fluctuations.
6.3 Common Abnormal Results in the Hexokinase Method
(1) Abnormal 340 nm background
Samples with high background absorbance at 340 nm can affect NADPH readings. A sample blank should be included, or the sample should be diluted before testing. Samples containing nucleic acids, protein lysates, or strong UV-absorbing substances require particular attention.
(2) Insufficient reaction components
Insufficiency of ATP, Mg²⁺, NADP⁺, HK, or G6PDH can all lead to underestimated results. When preparing reagents in-house, positive standards, linear range, and enzyme activity stability should be verified first.
(3) Effects of sample storage
Glucose can be continuously consumed in cell or blood samples. If blood samples are not promptly separated into plasma or treated with appropriate antiglycolytic measures, glucose concentration may decrease. Cell culture medium samples should also be processed or frozen as soon as possible after collection.
Table 3 Abnormal results and troubleshooting directions for three enzymatic glucose detection methods
Abnormal result | Possible method | Possible cause | Troubleshooting direction |
Low result | GOx method | Insufficient oxygen; H₂O₂ consumed by reducing substances | Dilute sample, check ascorbic acid/uric acid interference, verify enzyme activity |
High result | GOx method | High sample color or turbidity background | Set sample blank, centrifuge to remove turbidity |
Nonlinearity in high-concentration samples | GOx method, HK method | Insufficient substrate or coenzyme | Dilute sample, re-establish linear range |
High result in maltose background | Some GDH methods | Sugar cross-reactivity | Replace GDH system or verify using HK method |
Abnormal current signal | GDH electrochemical method | Electroactive substances or abnormal electrode status | Perform interference testing and quality control calibration |
High 340 nm background | HK method, GDH-NAD(P) method | Strong UV absorbance in sample | Set sample blank or dilute sample |
Large batch-to-batch variation | All three methods possible | Differences in enzyme activity, substrate, coenzyme, or instrument | Use quality control material and same-batch reagents |
Glucose decreases after storage | All three methods possible | Sample glycolysis or microbial consumption | Separate rapidly, store at low temperature, reduce standing time |
7 Reagent and Material Selection for Glucose Detection
Table 4 Core enzymes and activity assay products for the glucose oxidase method (GOD/GOx)
Application module | Cat. No. | Product Name | Grade/Specification | System Positioning |
Natural GOD/GOx | Glucose Oxidase (GOD) | EnzymoPure™, Native, ≥10000 GODU/g solid;from Aspergillus oryzae | Used for GOD-POD colorimetric systems, glucose oxidation reactions, and method development | |
Natural GOD/GOx | Glucose Oxidase from Aspergillus niger | EnzymoPure™,Native,≥100 U/mg enzyme powder | Suitable for routine glucose oxidase assays and method development for food or fermentation samples | |
Natural GOD/GOx | Glucose Oxidase from Aspergillus niger | Bioactive,ActiBioPure™,High Performance,EnzymoPure™,Lyophilized powder,≥180 U/mg enzyme powder | Suitable for GOD-POD colorimetric assays requiring higher enzyme activity and stability | |
Natural GOD/GOx | Glucose Oxidase（GOD） | EnzymoPure™, ≥50U/mg Lyophilized Powder | Used for glucose oxidation reactions, H₂O₂-coupled color development, and routine method validation | |
Natural GOD/GOx | Glucose Oxidase from Yeast | technical grade, ≥20 U/mg powder | Used for general enzymatic reactions, process systems, or non-clinical glucose oxidation research | |
Recombinant GOD/GOx | Recombinant Glucose Oxidase (GOD) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥180 U/mg enzyme powder | Used in recombinant GOD systems, suitable for method development requiring higher batch consistency | |
Recombinant GOD/GOx | Recombinant Glucose Oxidase (GOD) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE),≥150U/mg enzyme powder; ≥300U/mg protein | Used in high-purity recombinant GOD reaction systems; suitable for glucose oxidase method performance evaluation and sensor-related research | |
GOD activity assay | Glucose Oxidase (GOD) Activity Assay Kit (Micro Method) | BioReagent | Used to measure GOD activity; suitable for enzyme activity verification and batch quality control before preparing GOD-POD systems | |
GOD activity assay | Glucose Oxidase (GOD) Activity Assay Kit (Colorimetric Method) | BioReagent | Used to determine GOD activity by colorimetry; suitable for glucose oxidase raw material screening, stability evaluation, and method development quality control |
Table 5 Core enzymes and activity assay products for the glucose dehydrogenase method (GDH)
Application module | Cat. No. | Product Name | Grade/Specification | System Positioning |
GDH-FAD recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-FAD) | ActiBioPure™, Bioactive, High Performance, EnzymoPure™, Recombinant, ≥700 U/mg powder | Used in FAD-dependent GDH methods; suitable for oxygen-independent glucose detection, electrochemical sensing, and rapid detection systems | |
GDH-FAD recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-FAD) | ActiBioPure™, Bioactive, High Performance, EnzymoPure™, Recombinant, ≥95%(SDS-PAGE), ≥300 U/mg powder | Used in high-purity recombinant GDH-FAD systems; suitable for electrochemical glucose detection and sensor development | |
GDH-FAD recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-FAD) | ActiBioPure™, Bioactive, Recombinant, High Performance, EnzymoPure™, ≥475 U/mg powder | Used in recombinant GDH-FAD reaction systems; suitable for rapid glucose detection method development | |
GDH-FAD recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-FAD) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE),≥450 U/mg enzyme powder | Used in FAD-dependent glucose dehydrogenase methods; suitable for oxygen-unstable samples or electrochemical systems | |
GDH-FAD high-activity enzyme | Glucose Dehydrogenase (GDH-FAD) | Bioactive, ActiBioPure™, High Performance, EnzymoPure™, ≥90%(SDS-PAGE), ≥800 U/mg protein | Suitable for high-activity GDH-FAD system development; can be used for sensors, enzyme electrodes, or research-oriented glucose dehydrogenase methods | |
GDH-FAD natural enzyme | Glucose Dehydrogenase (GDH-FAD) from Aspergillus oryzae | ActiBioPure™, Bioactive, High Performance, EnzymoPure™, Native, ≥100 U/mg powder | Used in natural-source GDH-FAD reaction systems; suitable for method comparison and source-related studies | |
GDH-NAD recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-NAD) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE),≥200U/mg enzyme powder; ≥600U/mg protein | Used in NAD-dependent GDH methods; can quantify glucose or support enzymatic research through NADH signal at 340 nm | |
GDH-PQQ recombinant enzyme | Recombinant Glucose Dehydrogenase (GDH-PQQ) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥500 U/mg enzyme powder | Used in PQQ-dependent GDH systems; suitable for electrochemical detection research; cross-reactivity should be considered in complex carbohydrate samples | |
GDH conventional enzyme | Glucose Dehydrogenase from Bacillus | EnzymoPure™, ＞30U/mg | Used in basic GDH reaction systems; can serve as a material for routine enzymatic research and methodological comparison | |
GDH activity assay | Glucose Dehydrogenase (GDH) Activity Assay Kit (UV Micro Method) | BioReagent | Used for UV micro-method detection of GDH activity; suitable for enzyme activity quality control in GDH-NAD/GDH-NADP-related systems | |
GDH activity assay | Glucose Dehydrogenase (GDH) Activity Assay Kit (UV Colorimetric Method) | BioReagent | Used for UV colorimetric determination of GDH activity; suitable for enzyme raw material screening and reaction system optimization |
Table 6 Core enzymes and activity assay products for the hexokinase method (HK-G6PDH)
Application module | Cat. No. | Product Name | Grade/Specification | System Positioning |
HK core enzyme | Hexokinase (HK) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE),≥150 U/mg enzyme powder; ≥500 U/mg protein | Used in the first step of the HK-G6PDH glucose detection system to phosphorylate glucose into G6P | |
HK core enzyme | Hexokinase (HK) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥80%(SDS-PAGE),270-370 U/mg enzyme powder | Used for hexokinase-based glucose quantification, enzyme activity research, and method development | |
HK core enzyme | Hexokinase from Yeast(Lyophilized) | EnzymoPure™,ActiBioPure™,Bioactive,High Performance,≥150 units/mg protein | Used in yeast-derived HK systems; suitable for development of traditional HK-G6PDH detection systems | |
Recombinant HK | recombinant Hexokinase | EnzymoPure™, ≥150 units/mg | Used in recombinant hexokinase reaction systems; can be used for glucose detection method comparison | |
ADP-dependent HK | ADP-specific Glucokinase | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE), ≥500 U/mg protein | Suitable for ADP-dependent hexokinase reaction research; should be distinguished from conventional ATP-dependent HK-G6PDH glucose detection | |
ADP-dependent HK | ADP-specific Glucokinase | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥90%(SDS-PAGE), ≥500 U/mg protein | Used for alternative HK enzymology research; not recommended for direct mixing with conventional HK-G6PDH clinical detection systems | |
HK activity assay | Hexokinase (HK) Activity Assay Kit (WST-8, Micro Method) | BioReagent | Used to measure HK activity; suitable for enzyme activity verification of the glucose phosphorylation step and cellular/tissue glucose metabolism research | |
HK activity assay | Hexokinase (HK) Activity Assay Kit (UV Micro Method) | BioReagent | Used for HK activity detection in micro samples; suitable for glucose metabolism analysis in tissue homogenates or cell samples | |
HK activity assay | Hexokinase (HK) Activity Assay Kit (UV Colorimetric Method) | BioReagent | Used for UV macro-method determination of HK activity; suitable for enzyme activity quality control and metabolic pathway analysis | |
G6PDH core enzyme | Glucose-6-Phosphate Dehydrogenase (G6PD) | ActiBioPure™, Bioactive, High Performance, EnzymoPure™, ≥95%(SDS-PAGE), ≥600 U/mg protein | Used in the second step of the HK-G6PDH coupled system to oxidize G6P and generate NADPH | |
G6PDH NADP system | Glucose-6-phosphate Dehydrogenase from Leuconostoc mesenteroides | EnzymoPure™, ≥200 NADP units/mg protein | Suitable for NADP⁺-dependent G6PDH coupled reactions; can be used in 340 nm NADPH readout systems | |
G6PDH NADP system | Glucose-6-phosphate Dehydrogenase from Leuconostoc mesenteroides(Suspension) | EnzymoPure™, ≥200 NADP units/mg protein | Used in HK method coupled reactions or G6PDH enzymology studies; suitable for liquid enzyme preparation systems | |
G6PDH NAD system | Glucose-6-phosphate Dehydrogenase from Leuconostoc mesenteroides(Lyophilized) | EnzymoPure™, ≥360 NAD units/mg protein | Used in NAD-related G6PDH reaction systems; should be selected according to the cofactor system | |
G6PDH NAD system | Glucose-6-phosphate Dehydrogenase from Leuconostoc mesenteroides(Suspension) | Bioactive,ActiBioPure™,High Performance,EnzymoPure™,Native,≥360 NAD units/mg protein | Used in NAD-dependent G6PDH reaction research; must match the method system | |
High-activity G6PDH | Glucose-6-Phosphate Dehydrogenase from Leuconostoc mesenteroides(High-Activity,Suspension) | EnzymoPure™, ≥600 NAD units/mg protein | Used in high-activity G6PDH systems; suitable for coupled detection requiring higher reaction speed and sensitivity | |
G6PDH activity assay | Glucose-6-Phosphate Dehydrogenase (G6PDH) Activity Assay Kit (UV Micro Method) | BioReagent | Used to measure G6PDH activity; suitable for validating coupled enzyme activity in the HK-G6PDH system | |
G6PDH activity assay | Glucose-6-Phosphate Dehydrogenase (G6PDH) Activity Assay Kit (UV Colorimetric Method) | BioReagent | Used for UV colorimetric detection of G6PDH activity; suitable for methodological quality control and enzyme activity comparison |
Table 7 Selection of GOx-POD coupled colorimetric auxiliary materials
Application module | Cat. No. | Product Name | Grade/Specification | System Positioning |
High-purity HRP/POD | Horseradish Peroxidase (HRP) | Bioactive,ActiBioPure™,Native,High Performance,EnzymoPure™,from Horseradish; ≥250 U/mg enzyme powder; RZ≥3 | Used for H₂O₂-coupled color development in the GOD-POD colorimetric method; suitable for high-purity color development systems | |
High-activity HRP/POD | Horseradish Peroxidase (HRP) | Bioactive,ActiBioPure™,Native,High Performance,EnzymoPure™,≥300U/mg enzyme powder, Rz≥3; from Horseradish | Used in high-sensitivity GOD-POD colorimetric systems; suitable for low-concentration glucose detection or high-requirement method development | |
EIA-grade POD | Peroxidase from horseradish(EIA Grade,Purified) | EnzymoPure™, RZ 2.9,≥500 units/mg protein | Used in high-activity, high-purity POD color development systems; suitable for GOD-POD methods requiring high sensitivity | |
Routine HRP/POD | Horseradish Peroxidase (HRP) | EnzymoPure™, ＞200 U/mg, RZ 2-4 | Used in GOD-POD colorimetric detection, hydrogen peroxide color development reactions, and method development | |
Recombinant HRP/POD | Horseradish Peroxidase (HRP) | Bioactive,Recombinant,ActiBioPure™,High Performance,EnzymoPure™,≥250U/mg enzyme powder, Rz ≥3; expressed in Nicotiana benthamiana | Used in high-activity recombinant HRP color development systems; can be used for GOD-POD method optimization | |
POD stabilizing material | Peroxidase Stabilizing Buffer | liquid | Used for HRP/POD storage and optimization of reaction system stability | |
POD activity assay | Peroxidase (POD) Activity Assay Kit (Colorimetric Method) | BioReagent | Used for POD/HRP activity evaluation; suitable for coupled enzyme quality control in GOD-POD systems | |
HRP chromogenic substrate | ELISA Substrates for horseradish peroxidase (HRP) | fast2 | Can be used as a reference for HRP color development systems; when used for glucose detection, wavelength, linear range, and substrate stability must be verified |
8 Frequently Asked Questions
8.1 Which method should be preferred for routine laboratory glucose detection?
When the sample matrix is relatively simple, throughput is high, and the main instruments are ordinary microplate readers or spectrophotometers, the glucose oxidase method can be prioritized. If the sample background is complex, higher accuracy is required, or the result needs to be compared with clinical biochemical data, the hexokinase method can be prioritized.
8.2 Which method is suitable for glucose consumption assays in cell culture medium?
The glucose oxidase method is commonly used because it is simple to operate and suitable for batch microplate detection. A medium blank without seeded cells should be included, and results should be normalized to cell number, total protein, or cell viability to avoid misinterpreting cell death or proliferation differences as changes in glucose metabolism.
8.3 Why is blank correction more important for tissue homogenate samples?
Tissue homogenates may contain pigments, turbidity, reducing substances, and endogenous enzymes that affect color development reactions or absorbance readings. A sample blank should be included when using the GOx-POD method. If the background is too high or recovery is unsatisfactory, the hexokinase method can be considered for verification.
8.4 How should GDH-FAD, GDH-NAD, and GDH-PQQ be distinguished?
GDH-FAD is commonly used for electrochemical detection and sensor systems. GDH-NAD is more suitable for 340 nm spectrophotometric readout. GDH-PQQ is suitable for some electrochemical systems, but cross-reactivity with maltose, galactose, xylose, and other sugars should be considered in complex carbohydrate backgrounds.
8.5 Why is the hexokinase method more suitable for high-accuracy detection?
The hexokinase method generates NADPH through HK-G6PDH dual-enzyme coupling, and the signal comes from absorbance change at 340 nm. It does not depend on H₂O₂ color development reactions, so it is less affected by hydrogen peroxide scavengers and POD colorimetric system interference. Therefore, it is more suitable for clinical biochemical testing and complex sample verification.
The glucose oxidase method is suitable for routine colorimetric and high-throughput detection, the glucose dehydrogenase method is suitable for electrochemical sensing and rapid detection, and the hexokinase method is more suitable for high-accuracy quantification and complex sample verification. In practical applications, method selection should prioritize sample matrix, detection platform, and interference risk.
For more related articles, please see below:
[3] Glucose Oxidase: A Versatile Biocatalyst Across Multiple Fields
[4] Glucosidases: Classification Framework, Catalytic Mechanisms, and Application Essentials