| Description | Glutathione S-Transferase (GST) is a protein family with multiple physiological functions, primarily located within the cytoplasm. GST is a crucial component of the body's detoxification enzyme system. It mainly catalyzes the covalent binding of the sulfhydryl group of glutathione (GSH) to Glutathione S-Transferase (GST) is a protein family with multiple physiological functions, primarily located within the cytoplasm. GST is a crucial component of the body's detoxification enzyme system. It mainly catalyzes the covalent binding of the sulfhydryl group of glutathione (GSH) to various chemicals and their metabolites, converting electrophilic compounds into hydrophilic compounds that are more easily excreted in bile or urine. This process facilitates the degradation and elimination of potentially toxic substances from the body. Thus, GST plays a vital biological role in protecting cells from damage caused by electrophilic compounds. GST possesses GSH peroxidase activity (also known as non-Se-GSH-Px) and functions in repairing oxidatively damaged macromolecules such as DNA and proteins. The GST-catalyzed reaction consumes GSH but does not increase GSSG levels. Detection Principle: GST catalyzes the conjugation of GSH with CDNB (1-chloro-2,4-dinitrobenzene). The conjugation product has an absorption peak at 340 nm. The GST activity is calculated by measuring the rate of increase in absorbance at 340 nm. Detection Range: 2 - 76 U/L Sensitivity: 2 U/L Applicable Samples: Serum (plasma), animal/plant tissues, cells, bacteriaG1501773Component48T96TStorageG1501773AAssay Buffer60 mL120 mL2-8℃G1501773BChromogen11 mL22 mL2-8℃. Store in the dark.G1501773CSubstrate1EA1EA2-8℃. Store in the dark.Note: Before formal testing, it is recommended to perform a preliminary test with 2-3 samples expected to have significant differences.User-Prepared Instruments and ReagentsMicroplate reader or UV spectrophotometer (capable of measuring absorbance at 340 nm)96-well UV plate or micro quartz cuvettes, adjustable micropipettes and tipsIce maker, refrigerated centrifuge, water bathDeionized waterHomogenizer (for tissue samples)Experimental Procedure1. Reagent PreparationReagent NameReagent PreparationNotesAssay BufferReady-to-use; Equilibrate to room temperature before use.Store at 4℃.ChromogenReady-to-use; Equilibrate to room temperature before use.Store at 4°C protected from light. Skin irritant. Use appropriate protective equipment.Substrate Working ReagentBefore use, dissolve in 2.4 mL of deionized water.Unused reagent can be stored at 4°C protected from light for one month.2. Sample Preparation2.1 Animal/Plant TissuesWeigh 0.1 g of tissue sample. Add 1 mL of pre-cooled Assay Buffer and homogenize quickly on ice. Centrifuge the homogenate at 8,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.2 Cells or BacteriaCollect 5×10⁶ cells or bacteria into a centrifuge tube. Wash with cold PBS, centrifuge, and discard the supernatant. Add 1 mL of Assay Buffer. Sonicate in an ice bath for 5 minutes (power 20% or 200W, pulse 3s on, 7s off, repeat 30 times). Centrifuge at 8,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.3 Serum (Plasma)Assay directly.Note:Sample processing should be performed on ice. If not used immediately, samples can be stored at -80°C for one month.For GST activity measurement in cells, the cell count should be between 3-5×10⁶. Use Assay Buffer with sonication for cell extraction; do not use cell lysis buffers.If protein concentration measurement is required, Aladdin's BCA Protein Quantification Kit (B665595) or Ready-to-Use BCA Protein Quantification Kit (R1491648) is recommended.3. Assay Steps3.1 Preheat the microplate reader or UV spectrophotometer for at least 30 minutes. Set the wavelength to 340 nm. For UV spectrophotometers, zero the instrument with deionized water.3.2 Incubate the Substrate Working Reagent at 25°C (for general species) or 37°C (for mammals) for 15 minutes.3.3 Add reagents to a 96-well UV plate or micro quartz cuvette as follows:ReagentBlank (µL)Test (µL)Sample020Assay Buffer200Chromogen180180Substrate Working Reagent20203.4 Mix rapidly and immediately measure the change in absorbance at 340 nm. Record the absorbance for the Blank at 10 seconds (A1) and 310 seconds (A2). Record the absorbance for the Test at 10 seconds (A3) and 310 seconds (A4). Calculate ΔA blank = A2 - A1, ΔA test = A4 - A3. Note: Only one Blank is needed. A preliminary test with 2-3 samples showing expected significant differences is recommended. If the sample absorbance is greater than 1, dilute the sample with deionized water and multiply the result by the dilution factor. The reaction temperature significantly affects the results; maintain it at 25°C (general species) or 37°C (mammals). 4. Calculation of Results 4. Calculation of Results Note: We provide both derived and simplified calculation formulas. They are equivalent. The simplified formulas in bold are recommended for final calculation. 4.1 Calculation Formulas for 96-well UV Plate (1) Based on Protein Concentration Unit Definition: One unit of enzyme activity is defined as the amount that catalyzes the conjugation of 1 µmol of CDNB with GSH per minute per milligram of protein at 25°C or 37°C. Calculation Formula: GST Activity (U/mg prot) = (ΔAtest - ΔAblank) ÷ (ε × d) × 10⁶ × Vtotal reaction ÷ (Cpr × Vsample) ÷ T = 0.46 × (ΔAtest - ΔAblank) ÷ Cpr (2) Based on Sample Fresh Weight Unit Definition: One unit of enzyme activity is defined as the amount that catalyzes the conjugation of 1 µmol of CDNB with GSH per minute per gram of sample at 25°C or 37°C. Calculation Formula: GST Activity (U/g fresh weight) = (ΔAtest - ΔAblank) ÷ (ε × d) × 10⁶ × Vtotal reaction ÷ (Vsample ÷ Vtotal sample × W) ÷ T = 0.46 × (ΔAtest - ΔAblank) ÷ W (3) Based on Cell or Bacterial Count Unit Definition: One unit of enzyme activity is defined as the amount that catalyzes the conjugation of 1 µmol of CDNB with GSH per minute per 10⁴ cells or bacteria at 25°C or 37°C. Calculation Formula: GST Activity (U/10⁴) = (ΔAtest - ΔAblank) ÷ (ε × d) × 10⁶ × Vtotal reaction ÷ (500 × Vsample ÷ Vtotal sample) ÷ T = 0.46 × (ΔAtest - ΔAblank) ÷ 500 (4) Based on Liquid Volume Unit Definition: One unit of enzyme activity is defined as the amount that catalyzes the conjugation of 1 µmol of CDNB with GSH per minute per milliliter of liquid at 25°C or 37°C. Calculation Formula: GST Activity (U/mL) = (ΔAtest - ΔAblank) ÷ (ε × d) × 10⁶ × Vtotal reaction ÷ Vsample ÷ T = 0.46 × (ΔAtest - ΔAblank) 4.2 Calculation Formulas for Micro Quartz Cuvette Adjust the pathlength (d) in the formulas above from 0.5 cm to 1 cm for calculations. Parameter Definitions: ε: Molar extinction coefficient of the product, 9.6 × 10³ L/mol/cm d: Light path for 96-well plate (0.5 cm) 10⁶: Conversion factor (1 mol = 1 × 10⁶ µmol) V total reaction : Total reaction volume (220 µL = 2.2 × 10⁻⁴ L) Cpr: Protein concentration of the supernatant (mg/mL) W: Sample weight (g) V sample : Volume of supernatant added to the reaction system (20 µL = 0.02 mL) V total sample : Volume of extraction buffer added (1 mL) T: Reaction time (5 min) 500: Cell or bacterial count factor (5 × 10⁶ total cells / 10⁴ per unit = 500)Precautions1. Biochemical reagents are generally irritating and potentially biologically toxic. For your safety and health, implement appropriate biosafety precautions throughout the experiment, including wearing lab coats, masks, gloves, and head covers. Perform experiments in a fume hood or biosafety cabinet.2. This product is for research use only. Not for use in clinical diagnosis... Read More | Bacterial protein extraction reagents use mild non-ionic detergents and are suitable for extracting recombinant proteins expressed in Escherichia coli and insect cells. During the extraction process, there is no need for ultrasonic fragmentation, effectively avoiding contamination of exogenous Bacterial protein extraction reagents use mild non-ionic detergents and are suitable for extracting recombinant proteins expressed in Escherichia coli and insect cells. During the extraction process, there is no need for ultrasonic fragmentation, effectively avoiding contamination of exogenous proteins. This product can be applied to extract soluble proteins from bacterial lysates. The bacterial protein extraction kit adds a mixture of lysozyme, DNase I, and protease inhibitors to the extraction reagent, which can improve the efficiency of protein extraction and reduce the viscosity caused by DNA, effectively avoiding protein degradation. The extracted protein maintains biological activity and can be subjected to downstream operations such as IP, Western blot, and protein purification. Component B665764 100 preps Bacterial Protein Extraction Reagent 100 ml Protease Inhibitor Cocktail (100x) 1 ml Lysozyme （50 mg/ml） 200µl DNaseⅠ（1,000 U/ml） 100µl Notes:1. This product is suitable for extracting proteins from fresh or frozen bacterial and insect cells.2. This product uses Tris buffer system. Please use the same buffer system for protein purification after extraction.3. The protein lysis solution obtained from this product can be used for protein quantification using BCA or Bradford method.4. For special strains, if the extraction effect is not ideal, the sample can be frozen before protein extraction.5. Depending on the specific situation, protease inhibitors, salts, chelating agents, reducing agents, etc. can be added to this product.Operation steps: ● Insect cell protein extraction1. Collect cells by low-speed centrifugation. Add 10 to every 1 ml of Bacterial Protein Extraction Agent µ The Protein Inhibitor Cocktail is 1 x working fluid.2. Weigh the wet weight of the cells and add 1 x working solution at a rate of 10 ml/g.3. After resuspension, incubate on ice for 20 minutes (the ice storage time should be adjusted according to different cell types).Centrifuge at 4.15000 × g for 15 minutes to isolate soluble proteins. ● Extraction of soluble bacterial proteins 1. Centrifuge for 10 minutes at a rate of 5000 × g and collect the bacterial cells.2. Optional steps: Add 1 ml of Bacterial Protein Extraction Reagent every 1 ml µ DNase I (1000 U/ml), 2 µ Lysozyme (50 mg/ml) and 10 µ Protein Inhibitor Cocktail, vortex oscillation and mixing. 3. Add 20 ml of Bacterial Protein Extraction Reagent to each gram of bacterial precipitate, and add the extraction solution to the bacterial precipitate. Vortex thoroughly or use a pipette to blow up and down until the bacterial precipitate is completely resuspended.4. After resuspension, incubate at room temperature for 10-15 minutes (the storage time should be adjusted according to different cell types). 5. Centrifuge at 15000 × g for 5 minutes.6. Transfer the supernatant to a new centrifuge tube (the supernatant is soluble protein) for protein quantification and downstream experiments.Note: If the target protein exists in the form of inclusion bodies, inclusion body protein solution can be used for dissolution or expression conditions can be optimized to increase the expression of soluble proteins.Frequently asked questions: Problem Possible reasons Resolvent The target protein is insoluble The target protein is expressed as an inclusion body Optimize expression conditions or add Lysozyme and DNase I to protein extraction reagents using inclusion body protein solution After adding Lysozyme, the target protein has not been extracted yet Temperature too low Restore the reagent to room temperature After adding Lysozyme, the target protein has not been extracted yet Lysozyme Decreased or inactivated activity Add more Lysozymes or replace with new enzymes Extract has high viscosity DNase I Decreased or inactivated activity Add more DNase I or replace with a new DNase I to increase the final concentration of magnesium ions to 2 mM After protein extraction, most of the proteins still exist in the precipitate Excessive protein content Add Lysozyme and DNase I The protein extraction reagent has sediment precipitation Temperature too low Restore the protein extraction reagent to room temperature... Read More | D-Lactate, typically present in the bloodstream at nanomolar concentrations, is produced by an intestinal source or via the methylglyoxal pathway. In mammals, D-Lactate metabolism requires D-Lactate hydrogenase and is metabolized slowly, thus an increase in blood concentration levels can lead to D-Lactate, typically present in the bloodstream at nanomolar concentrations, is produced by an intestinal source or via the methylglyoxal pathway. In mammals, D-Lactate metabolism requires D-Lactate hydrogenase and is metabolized slowly, thus an increase in blood concentration levels can lead to acidemia and acidosis. The severity of this D-lactic acidosis can be associated with neurotoxic symptoms. Significant D-Lactate accumulations in the body can also be related to impaired metabolism and excretion.D-Lactate Colorimetric Assay kit has been used to determine the stereospecificity of lactate produced.Suitability: Suitable for use with samples of serum, plasma, cells, culture and fermentation media.Principle: In this assay, D-Lactate is specifically oxidized by D-Lactate hydrogenase and generates a proportional colorimetric product measured at 450 nm. The useful concentration range in samples is 0.1-10 mM D-Lactate... Read More | In the experimental process of molecular biology, Fluo ™ Green ® The dsDNA quantification kit is a product used for fluorescence detection and quantification of double stranded DNAThe method is very sensitive. Commonly used in molecular biology techniques: construction of cDNA libraries; In the experimental process of molecular biology, Fluo ™ Green ® The dsDNA quantification kit is a product used for fluorescence detection and quantification of double stranded DNAThe method is very sensitive. Commonly used in molecular biology techniques: construction of cDNA libraries; Purification and application of DNA fragments for subcloning, such as DNA quantification, product amplification, and further detection of primers. Vaccines are a commonly used control method in modern disease prevention. Nowadays, many vaccines are cell culture vaccines, such as recombinant hepatitis B vaccine, rabies vaccine and most other vaccines are produced by cell culture. Among them, the purification of vaccines is a key issue, and we need to remove host cell DNA and host proteins as much as possible. If the DNA and protein of the host cell are injected into the human body together with the vaccine, unpredictable consequences will occur.The conventional method for detecting DNA content is to measure its absorbance at 260nm (A260). The main disadvantage of this method is that nucleotides, single stranded nucleic acids, and proteins have a significant impact on the signal, and are also subject to interference from pollutants during the nucleic acid preparation process, making it difficult to distinguish between DNA and RNA. Additionally, this method is insensitive (5 µ g/mL dsDNA solution A260=0.1). Fluo ™ The Green quantitative detection method is simple and convenient, and has been selected by multiple biological product factories, becoming the standard for residual DNA detection in biological products.At present, this method has been included in the 2010 edition of the Chinese PharmacopoeiaPrinciple:Fluo ™ Green emits fluorescence only after binding to double stranded DNA, and does not emit fluorescence without DNA; The fluorescence emitted is directly proportional to the concentration of DNA. In the 2010 Chinese Pharmacopoeia, it was proposed that, Fluo ™ The detection limit of Green's quantitative DNA method is about 0.3ng/ml, and the linearity is good (R2>0.99) when the DNA content is in the range of 1.25-80ng/mLAdvantage:1) This method can determine double stranded DNA from any expressed host sample.2) It is possible to directly quantify PCR amplification products without purifying DNA from the reaction mixture.3) Far exceeding the sensitivity of traditional UV A260 detection methods and Hoechst33258.4) Higher concentrations of salt, urea, ethanol, chloroform, detergents, proteins, or agarose have no effect on the measurement.5) The effect of measuring dsDNA in the presence of equimolar concentrations of ssDNA and RNA is minimal.Required equipment• Micro fluorescence meter; Portable fluorescence analyzer - Shanghai Huguo Scientific Instrument Co., Ltd. HG-9 model; 1cm quartz colorimetric dish• Fluo ™ Green dsDNA quantitative detection kit, 1mL of concentrated reagent solution is sufficient for 200 measurements of 2mL volume.1×TE（10mM Tris 1mM EDTA）pH8.0； 250ug/mL calf thymus DNAExperimental planPreparation of reagentsFluo ™ The Green dsDNA quantification reagent is stored in anhydrous DMSO (dimethyl sulfoxide) in the form of 1mL concentrated solution. On the day of the experiment, prepare2X Fluo ™ The operating solution of Green's reagent was diluted with 1xTE at a ratio of 1:200 in concentrated solution (10mM Tris HCl,1mM EDTA, pH 7.5). If you want to prepare enough operating solution to determine 20 samples, you can add 100 µ L Fluo to 20mL1x TE ™ Green dsDNA quantification reagent. Due to the easy adsorption of reagents onto glass surfaces, they need to be prepared in plastic containers. Fluo ™ Green reagent is easily degraded by light, so the prepared solution should be wrapped in foil or stored in a dark place away from light.It is best to use the solution within a few hours of preparation to ensure optimal results.Experimental method:1). Preparation of standard working fluid:1mg of calf thymidine DNA dry powder (Tris, NaCl, and other concentrations have become standard systems) is added to 1mL of double distilled water to prepare a 1mg/mL standard working solution;2). Configuration of dye working fluid:6 uL Fluo ™ Add 1mL of TE to Green (note: use 1 × TE to mix Fluo) ™ Dilute Green 200 times, use and prepare immediately, avoid light.3). Dilution of standard working fluid:(1) Mother liquor dilution: Take 10ul (1mg ⁄ mL) of standard working solution and add it to 990ul TE solution to dilute the concentration to 10ug ⁄ mL. Take 10ul (10ug ⁄ mL) of standard working solution and add it to 990ul TE solution to dilute the concentration to 100ng ⁄ mL;(2) Dilute by multiple ratio: Take 800ul (100ng ⁄ mL) of standard working solution and add it to 200ul of TE solution to achieve a concentration of 80ng ⁄ mL (pharmacopoeia regulation: fluorescent)The light staining method shows good linearity in the range of 1.25-80 ng/mL for DNA content, with a detection limit of 0.3 ng/mL. Take 500ul (80ng ⁄ mL) of standard working solution and add it to 500ul TE solution, diluting the concentration to 40ng ⁄ mL; Dilute sequentially by multiple ratios to prepare 20ng/ml 10ng/ml 5.0ng/ml 2.5ng/ml1.25ng/ml and 0.625ng/ml standard solution;4). Preparation of standard curve: Take 100ul of each gradient standard solution and dye working solution diluted by multiple ratios, mix well, and leave them at room temperature in the dark for 5 minutes. Use FB-15 portable fluorescence analyzer to detect the fluorescence value of the sample: Add the mixed solution to the microcalorimeter, make sure not to introduce bubbles into the sample, and gently tap the outside of the microcalorimeter to disperse the bubbles. Measure the fluorescence values of the sample and blank control using 1 × TE buffer as a blank; Corresponding to the concentration of standard solution (ng/ml)Perform linear regression on fluorescence intensity and prepare a standard curve.5). Measure the fluorescence value of the remaining samples. The fluorescence meter will provide a direct concentration reading, which can be used to generate a standard curve of DNA concentration. Final concentration of DNA to be tested Fluorescence reading value (ng/ml) / 100 6210 50 3195 40 2507 20 1261 10 620.8 5 298 4 258.8 2 152 0.5 43.8 0 0.72... Read More | Inquire |