| Description | Polyphenol Oxidase (PPO, EC1.10.3.1) is widely found in the plastids of plants, fungi, and insects. It is a copper-containing oxidase that can oxidize monophenols and diphenols to produce quinones, leading to browning. It is closely related to fruit and vegetable processing, tea quality, and Polyphenol Oxidase (PPO, EC1.10.3.1) is widely found in the plastids of plants, fungi, and insects. It is a copper-containing oxidase that can oxidize monophenols and diphenols to produce quinones, leading to browning. It is closely related to fruit and vegetable processing, tea quality, and tissue culture. The Plant Polyphenol Oxidase (PPO) Activity Assay Kit (Catechol, Micro method) provides a simple method to detect the activity level of polyphenol oxidase (PPO) in plant tissue samples.Detection Principle: Polyphenol oxidase (PPO) in the sample catalyzes the oxidation of catechol to produce quinones, which have a characteristic absorption peak at 410 nm. The rate of increase in absorbance at 410 nm is measured to calculate PPO activity.P1501774Component48T96TStorageP1501774AExtraction Buffer60 mL120 mL2-8℃P1501774BReagentⅠ24 mL48 mL2-8℃P1501774CReagentⅡ6 mL12 mL2-8℃. 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 visible spectrophotometer (capable of measuring absorbance at 410 nm)96-well plate or micro glass cuvettes, adjustable micropipettes and tipsRefrigerated centrifuge, ice maker, constant temperature water bathDeionized waterHomogenizerExperimental Procedure1. Reagent PreparationReagent NameReagent PreparationNotesExtraction BufferReady-to-use; Equilibrate to room temperature before use.Store at 4°C.ReagentⅠReady-to-use; Equilibrate to room temperature before use.Store at 4°C.ReagentⅡReady-to-use; Equilibrate to room temperature before use.Store at 4°C protected from light; Toxic, handle with care.2. Sample PreparationNote: Fresh samples are recommended. If not used immediately, samples can be stored at -80°C for one month.2.1 Preparation of Crude Enzyme ExtractHomogenize the plant sample in ice-cold Extraction Buffer with a mass (g) to volume (mL) ratio of 1:5 to 1:10 (recommended: 0.1 g tissue + 1 mL Extraction Buffer). Centrifuge the homogenate at 8,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.2.2 Boiled Sample ControlTake an appropriate amount of the crude enzyme extract and heat it in a boiling water bath for 5 minutes (seal to prevent moisture loss). Cool to room temperature.3. Assay Steps3.1 Preheat the microplate reader or visible spectrophotometer for at least 30 minutes. Set the wavelength to 410 nm. For spectrophotometers, zero the instrument with deionized water.3.2 Sample Measurement (Add reagents sequentially into 1.5 mL microcentrifuge tubes):ReagentControl Tube (µL)Test Tube (µL)Boiled Sample500Sample (supernatant)050ReagentⅠ200200ReagentⅡ50503.3 Mix thoroughly. Incubate in a 25°C water bath for 10 minutes, then immediately transfer to a boiling water bath for 10 minutes. After mixing, centrifuge at 5,000 g, 25°C for 10 minutes. Collect the supernatant. Transfer 200 µL of the supernatant to a micro glass cuvette or 96-well plate. Measure the absorbance of both the Test tube and Control tube at 410 nm. Calculate ΔA = Atest - Acontrol.Note:Each test tube requires a corresponding control tube.It is recommended to perform a preliminary test with 2-3 samples expected to have significant differences before the formal experiment.The optimal reaction temperature for PPO may vary slightly among different samples and can be adjusted between 25-37°C.If the sample absorbance is less than 0.02, consider increasing the sample volume appropriately. If the sample absorbance is greater than 1, it is advisable to dilute the sample before assay.4. Calculation of ResultsNote: We provide both the derived formula and a simplified formula. They are equivalent. It is recommended to use the simplified formula in bold for final calculation.4.1 Calculation Formula when using a 96-well plate:Unit Definition: One unit of enzyme activity is defined as the amount that causes a change of 0.005 in absorbance at 410 nm per minute per gram of tissue per mL of reaction mixture.PPO Activity (U/g fresh weight) = ΔA × Vtotal reaction÷ (W × Vsample / Vtotal sample ) ÷ 0.005 ÷ T = 120 × ΔA / W4.2 Calculation Formula when using a micro glass cuvette:Unit Definition: One unit of enzyme activity is defined as the amount that causes a change of 0.01 in absorbance at 410 nm per minute per gram of tissue per mL of reaction mixture.PPO Activity (U/g fresh weight) = ΔA × Vtotal reaction ÷ (W × V sample / Vtotal sample ) ÷ 0.01 ÷ T = 60 × ΔA / WParameter Definitions:Vtotal reaction: Total volume of the reaction system (0.3 mL)Vsample : Volume of sample added to the reaction (0.05 mL)Vtotal sample : Volume of Extraction Buffer added during homogenization (1 mL)T: Reaction time (10 minutes)W: Sample weight (g)PrecautionsThis product is for research use only. Not for use in clinical diagnosis. For your safety and health, please wear lab coats and disposable gloves during operation... Read More | Inquire | DescriptionCholesteryl ester transfer protein (CETP) is present in normal human plasma and transfers neutral lipids from high density lipoproteins (HDL) to very low density lipoprotein (VLDL) and low density lipoprotein (LDL). CETP plays an important role in lipoprotein metabolism and influences theDescriptionCholesteryl ester transfer protein (CETP) is present in normal human plasma and transfers neutral lipids from high density lipoproteins (HDL) to very low density lipoprotein (VLDL) and low density lipoprotein (LDL). CETP plays an important role in lipoprotein metabolism and influences the reverse cholesterol transport pathway.Preparation instructionsSuitable for high-throughput screening (HTS), mechanism of action (MOA) studies, and structure-activity relationship (SAR) work in CETP sources.PrincipleThe CETP RP Activity Assay uses a proprietary substrate that enables the detection of CETP-mediated neutral lipid mass transfer. The method is useful for measuring CETP activity in recombinant protein (RP) or purified CETP samples and has a high D... Read More | Products contentN665993Component240 TStorageN665993AIndex N501 Primers for Illumina240 µL-20℃. Avoid freeze/ Thaw cycle.N665993BIndex N925-N948 Primers for Illumina24×10 µL-20℃. Avoid freeze/ Thaw cycle. Products Introduction This kit is a companion kit to the transposase-Products contentN665993Component240 TStorageN665993AIndex N501 Primers for Illumina240 µL-20℃. Avoid freeze/ Thaw cycle.N665993BIndex N925-N948 Primers for Illumina24×10 µL-20℃. Avoid freeze/ Thaw cycle. Products Introduction This kit is a companion kit to the transposase-based Rapid DNA Library Construction Kit for Illumina platform library construction. Each kit contains one N5 primer and 24 N7 primers, which can be used to prepare 24 different single-ended Index libraries. All reagents provided in the kits have been subjected to stringent quality control and functional validation to maximize the stability and reproducibility of library construction. The libraries can be used for sequencing on Illumina platforms such as HiSeq X-10/4000/2500/2000 and MiSeq. Provide your own instruments, reagents and consumables1. Magnetic frame: DynaMagTM-2 is recommended.2. DNA purification and recovery kit: It is recommended to use Kangwei DNA purification and recovery kit by magnetic bead method.3. DNA building kit: It is recommended to use the Kangwei Century transposase method second-generation sequencing rapid DNA building kit.4. Anhydrous ethanol.5. Reaction tubes: It is recommended to use low adsorption PCR tubes with 1.5 ml centrifuge tubes;Tip: It is recommended to use a high quality filter tip to prevent contamination of kits and library samples. Pre-experiment Preparation and Important NotesPlease centrifuge briefly before opening the cap so that the liquid collects at the bottom of the tube to avoid cross-contamination between different primers. ProcedureFor the use of the CombiVision Second Generation Sequencing Multisample Primer Kit, please follow the CombiVision Second Generation Sequencing Rapid DNA Library Kit protocol.Index N501 Primer for IlluminaIndex N901-N996 Primer for Illumina... Read More | V669947 Component 50T Storage V669947A Buffer GL 15 mL RT V669947B Buffer GW1 (concentrate) 13 mL RT V669947C Buffer GW2 (concentrate) 15 mL RT V669947D Buffer RE 10 mL RT V669947E Proteinase K 12.5 mg RT V669947F Proteinase K Storage Buffer 1.25 mL RT V669947G Spin Columns RS with Collection Tubes V669947 Component 50T Storage V669947A Buffer GL 15 mL RT V669947B Buffer GW1 (concentrate) 13 mL RT V669947C Buffer GW2 (concentrate) 15 mL RT V669947D Buffer RE 10 mL RT V669947E Proteinase K 12.5 mg RT V669947F Proteinase K Storage Buffer 1.25 mL RT V669947G Spin Columns RS with Collection Tubes 50 RT V669947H RNase-Free Centrifuge Tubes (1.5 mL) 50 RTProductsThis kit is suitable for the extraction of viral RNA and DNA from fresh or frozen plasma, serum and cell-free body fluids. It is easy to operate as it does not require the use of organic solvents such as phenol and chloroform for extraction. The kit uses a unique buffer system to enable efficient and specific binding of viral nucleic acids in lysate to silica gel centrifugal adsorption columns. Inhibitors of PCR and enzyme reactions as well as residual impurities can be efficiently removed in a two-step effective rinsing step, and finally high purity viral nucleic acids can be obtained by using a low-salt buffer or water for elution. The purified viral nucleic acid is free of protein, nuclease and other impurities, and can be used directly in PCR, RT-PCR, Real-Time PCR, blotting experiments and so on.Self-contained reagent: anhydrous ethanol.Pre-experiment and Important Notes1. Add 1.25ml Proteinase K Storage Buffer to Proteinase K to dissolve it and store it at -20℃. Do not leave the prepared Proteinase K at room temperature for a long time, and avoid repeated freezing and thawing to avoid affecting its activity. Do not add Proteinase K directly into Buffer GL.2. Repeated freezing and thawing of the sample should be avoided, as this may result in smaller DNA fragments and a decrease in the amount of extracted DNA.3. Avoid repeated freezing and thawing of serum or plasma, which can lead to protein denaturation or precipitation, reducing the viral titer and thus affecting the yield of extracted viral nucleic acids.4. Anhydrous ethanol should be added to Buffer GW1 and Buffer GW2 according to the label instructions of the reagent bottle before first use.5. Check Buffer GL for crystallization or precipitation before use. If crystallization or precipitation occurs, redissolve Buffer GL in a water bath at 56℃.Procedure1. Take a 1.5 ml centrifuge tube (self-provided) and add 20 µl Proteinase K.2. Add 200 µl serum or plasma to the centrifuge tube. Add 200µl Buffer GL and vortex and shake for 15 seconds.Note: 1) Sample volume less than 200 µl can be made up by adding 0.9% NaCl (self-provided). 2) In order to ensure effective lysis of the sample, the sample needs to be mixed well with Buffer GL after adding Buffer GL.3. Incubate at 56°C for 15 minutes, centrifuge briefly, and collect the solution from the wall of the tube to the bottom of the tube.4. 250 µl of anhydrous ethanol was added, vortexed and shaken for 15 seconds, left at room temperature for 5 minutes, centrifuged briefly, and the solution on the wall of the tube was collected at the bottom of the tube.Note: If the ambient temperature exceeds 25°C, anhydrous ethanol should be used after pre-cooling on ice.5. Add the solution obtained in step 4 to the adsorbent column (RNase-Free Columns RS) that has been loaded into the collection tube, and if the solution cannot be added at one time, it can be transferred in several times. centrifuge the column at 12,000 rpm (~13,400 × g) for 1 min, pour off the waste liquid in the collection tube, and put the column back into the collection tube.6. Add 500 µl of Buffer GW1 to the adsorption column (check that anhydrous ethanol has been added before use), centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorption column back into the collection tube.7. Add 500 µl of Buffer GW2 to the adsorption column (check that anhydrous ethanol has been added before use), centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube, and put the adsorption column back into the collection tube.Note: Step 7 can be repeated if further DNA purity is required.8. Add 500 µl of anhydrous ethanol to the adsorbent column and centrifuge at 12,000 rpm for 1 min. Pour off the waste liquid in the collection tube and put the adsorbent column back into the collection tube.9. Centrifuge at 12,000 rpm for 3 minutes and pour off the waste liquid in the collection tube. Leave the adsorption column at room temperature for several minutes to dry thoroughly.Note: The purpose of this step is the removal of residual ethanol from the adsorbent column; ethanol residue can interfere with subsequent enzymatic reactions (digestion, PCR, etc.).10. Place the adsorption column in a new collection tube (RNase-Free Centrifuge Tube), add 20-150 µl of Buffer RE or sterilized water overhanging the middle of the adsorption column membrane, leave it at room temperature for 2-5 minutes, and then centrifuge it at 12,000 rpm for 1 minute to collect the nucleic acid solution.Note: 1) If the downstream experiment is sensitive to pH or EDTA, you can use sterilized water for elution. The pH of the eluent has a great influence on the elution efficiency, if water is used as the eluent it should be ensured that its pH is 7.0-8.5 (the pH of water can be adjusted to this range with NaOH), and the elution efficiency is not high when the pH is lower than 7.0.(2) For long-term storage, please store the DNA solution at -20℃ and the RNA solution at -70℃.3) If the final concentration of DNA/RNA is to be increased, the DNA/RNA eluate obtained in step 10 can be re-spiked onto the adsorbent membrane and step 10 repeated... Read More |