| Description | Catalase (CAT, EC 1.11.1.6) is widely found in animals, plants, microorganisms, and cultured cells. It is the primary H₂O₂-scavenging enzyme and plays a crucial role in the reactive oxygen species (ROS) scavenging system. H₂O₂ has a characteristic absorption peak at 240 nm. Catalase (CAT, EC 1.11.1.6) is widely found in animals, plants, microorganisms, and cultured cells. It is the primary H₂O₂-scavenging enzyme and plays a crucial role in the reactive oxygen species (ROS) scavenging system. H₂O₂ has a characteristic absorption peak at 240 nm. CAT decomposes H₂O₂, causing the absorbance of the reaction solution at 240 nm to decrease over time. The CAT activity can be calculated based on the rate of change in absorbance.Component50TStorageExtraction Buffer60 mL2-8℃Working Solution60 mL2-8℃User-Prepared Instruments and ReagentsUV spectrophotometer, benchtop centrifuge, adjustable pipettes, 1 mL quartz cuvette, mortar, ice, and distilled water.Experimental Procedure1. Crude Enzyme Extract Preparation1.1 Bacterial/Cell SamplesCollect bacteria or cells into a centrifuge tube, centrifuge, and discard the supernatant. Use a bacteria/cell count (10⁴) to Extraction Buffer volume (mL) ratio between 500:1 and 1000:1 (recommended: 5 million bacteria/cells in 1 mL Extraction Buffer). Disrupt the bacteria or cells by sonication (ice bath, power 20% or 200W, pulse 3s on, 10s off, repeat 30 times). Centrifuge at 8,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.1.2 Tissue SamplesUse a tissue mass (g) to Extraction Buffer volume (mL) ratio between 1:5 and 1:10 (recommended: weigh approx. 0.1 g tissue, add 1 mL Extraction Buffer). Homogenize in an ice bath. Centrifuge at 8,000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.1.3 Serum (Plasma) SamplesAssay directly.2. Assay Steps2.1 Preheat the spectrophotometer for at least 30 minutes. Set the wavelength to 240 nm. Zero the instrument with distilled water.2.2 Before assay, incubate the CAT Working Solution in a water bath at 37°C (for mammals) or 25°C (for other species) for 10 minutes.2.3 Add 35 µL of sample and 1 mL of Working Solution into a 1 mL quartz cuvette. Mix well and immediately measure the initial absorbance at 240 nm (A₁). Measure the absorbance again after 1 minute (A₂). Calculate ΔA = A₁ - A₂.3. CAT Activity Calculation3.1 Calculation of CAT Activity in Serum (Plasma)Unit Definition: One unit of enzyme activity is defined as the amount that catalyzes the degradation of 1 nmol of H₂O₂ per minute per milliliter of serum (plasma).Derived Formula:CAT Activity (nmol/min/mL) = [ΔA × Vtotal reaction÷ (ε × d) × 10⁹] ÷ Vsample÷ TSimplified Formula:CAT Activity (nmol/min/mL) = 678 × ΔA3.2 Calculation of CAT Activity in Tissues, Bacteria, or Cells(1) Based on Sample Protein ConcentrationUnit Definition: One unit of enzyme activity is defined as the amount that catalyzes the degradation of 1 nmol of H₂O₂ per minute per milligram of tissue protein.Derived Formula:CAT Activity (nmol/min/mg prot) = [ΔA × Vtotal reaction÷ (ε × d) × 10⁹] ÷ (Vsample× Cpr) ÷ TSimplified Formula:CAT Activity (nmol/min/mg prot) = 678 × ΔA ÷ Cpr(2) Based on Sample Fresh WeightUnit Definition: One unit of enzyme activity is defined as the amount that catalyzes the degradation of 1 nmol of H₂O₂ per minute per gram of tissue.Derived Formula:CAT Activity (nmol/min/g fresh weight) = [ΔA × Vtotal reaction÷ (ε × d) × 10⁹] ÷ (W × Vsample÷ Vtotal sample) ÷ TSimplified Formula:CAT Activity (nmol/min/g fresh weight) = 678 × ΔA ÷ W(3) Based on Bacterial or Cell DensityUnit Definition: One unit of enzyme activity is defined as the amount that catalyzes the degradation of 1 nmol of H₂O₂ per minute per 10⁴ bacteria or cells.Derived Formula:CAT Activity (nmol/min/10⁴ cells) = [ΔA × Vtotal reaction÷ (ε × d) × 10⁹] ÷ (500 × Vsample÷ Vtotal sample) ÷ TSimplified Formula:CAT Activity (nmol/min/10⁴ cells) = 1.356 × ΔAParameter Definitions:1.ΔA: Change in absorbance (A₁ - A₂)2.Vtotal reaction: Total reaction volume (1.035 × 10⁻³ L)3.ε: Molar extinction coefficient of H₂O₂ (4.36 × 10⁴ L/mol/cm)4.d: Light path length of the cuvette (1 cm)5.10⁹: Unit conversion factor (1 mole = 10⁹ nmoles)6.Vsample: Volume of sample added to the reaction (0.035 mL)7.T: Reaction time (1 min)8.Cpr: Sample protein concentration (mg/mL)9.W: Sample weight (g)10.Vtotal sample: Total volume of extraction buffer added (1 mL)11.500: Total number of bacteria or cells (5 million)Precautions1.Before formal testing, it is essential to perform a preliminary test with 2-3 samples expected to have significant differences.2.This product is for research use only. Not for use in clinical diagnosis.Frequently Asked Questions (FAQ)Q: What should I do if I get a negative value?A: Check if bubbles formed during the reaction. Excessive bubbling indicates very high enzyme activity, and bubbles can interfere, causing negative values. Try diluting the sample 10-fold with Extraction Buffer and re-assaying. If no bubbles form (with diluted sample or original reaction) and a small negative value persists, it indicates that the enzyme activity in this sample is below the detection limit... Read More | Inquire | Products contentN665954Component24 T96 TStorageN665954ATPS V136 µL144 µL-20℃. Avoid freeze/thaw cycle.N665954B5×FA Reaction Buffer96 µL384 µL-20℃. Avoid freeze/thaw cycle.N665954CTS Buffer72 µL288 µL-20℃. Avoid freeze/thaw cycle.N665954D2× Products contentN665954Component24 T96 TStorageN665954ATPS V136 µL144 µL-20℃. Avoid freeze/thaw cycle.N665954B5×FA Reaction Buffer96 µL384 µL-20℃. Avoid freeze/thaw cycle.N665954CTS Buffer72 µL288 µL-20℃. Avoid freeze/thaw cycle.N665954D2× PCR Mix600 µL2×1.2 mL-20℃. Avoid freeze/thaw cycle. * This kit is suitable for human genomic DNA library construction, the starting template DNA input amount is 1 ng, our company also has 50 ng and 5 ng of human genomic DNA starting transposase method library construction kit, in order to get a higher quality library, different starting amount of DNA is recommended to use different kits. Products IntroductionThis kit is developed for Illumina's high-throughput sequencing platform and provides the enzyme premix system and reaction buffer for genomic DNA library construction, including all components except PCR primers. Compared with the traditional library construction kits, this kit adopts the new transposase method for library construction, which can complete DNA fragmentation, end repair and junction reaction in one simple enzymatic reaction, significantly reducing the amount of template, reducing the number of experimental steps, and shortening the time of library construction; it adopts the high-fidelity DNA polymerase for library enrichment, and the preference-free PCR amplification can expand the coverage area of the sequence, which can be used for efficient and effective sequencing. The use of high-fidelity DNA polymerase for library enrichment and preference-free PCR amplification broadens the coverage area of the sequence and enables efficient preparation of DNA libraries for Illumina's second-generation sequencing platform. The kit is suitable for use with 1 ng of starting template DNA, and all reagents in the kit have been subjected to stringent quality control and functional validation to maximize the stability and reproducibility of library construction.Product Features● DNA fragmentation and junction ligation in one step.● Ultra-fidelity amplification minimizes amplification preference.Provide your own instruments, kits 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. Library PCR primer kit: It is recommended to use Kangwei transposase method for second generation sequencing multi-sample primer kit.4. Anhydrous ethanol, deionized water (pH between 7.0 and 8.0).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 Notes1. Avoid repeated freezing and thawing of reagents.2. PCR products are easily contaminated due to improper operation, resulting in inaccurate results. It is recommended to isolate the PCR reaction system preparation area from the PCR product purification area, and to use special pipettes to clean the experimental areas at regular intervals.3. Bead purification: the beads should be equilibrated to room temperature before use, all operations on the beads should be carried out at room temperature, 80% ethanol should be dispensed freshly, the beads should be rinsed and dried until the surface is free of liquid reflections and has a frosted appearance, insufficient drying of the beads will cause ethanol residue that will affect the subsequent experiments, and over-drying of the beads will affect the efficiency of DNA recovery.4. The kit is suitable for human genomic DNA library construction, if the DNA sample is a PCR product, it should be ensured that its length>.500 bp, since transposases do not work on DNA ends, it is recommended to extend the PCR product by 50-100 bp at each end of the PCR product to avoid low coverage of the ends for sequencing. Sample PreparationDNA purity requirement: A260/A280 = 1.8-2.0. Sample DNA: dissolved in ultrapure water.DNA quantification: Too much or too little DNA will affect the quality of the library. It is recommended to use Nano to test the purity of the genomic DNA and then use Qubit to test the concentration of the genome (do not use any absorbance-based assay for template quantification). Schematic diagram of DNA banking process procedureDNA fragmentation, junction reaction 1. Add the following reagents to a 200 µl PCR tube:2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube.3. Place the above PCR tubes in the PCR instrument with the hot cap on and program the reaction as follows:inactivation reactionAfter the DNA is fragmented, the enzyme is still in a high active state, so it should be removed from the PCR instrument immediately and terminated by adding the Reaction Termination Buffer, in order to prevent the DNA from being fragmented too much and resulting in smaller library fragments.1. Add 3 µl of TS Buffer to the PCR tube containing the fragmentation product.2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube.3. Incubate at room temperature for 5 min, or if the room temperature is too low, place the reaction on a PCR instrument at 25°C with the thermal cover closed.PCR amplification1. Add the following reagents to a 200 µl PCR tube.2. Mix by gently blowing with a pipette and centrifuge briefly so that all components are collected at the bottom of the tube. 3. Place the above PCR tubes in the PCR instrument with the thermal cap open, and the reaction program is as follows:Selective recovery of library DNA fragmentsIt is recommended to use CombiVision Magnetic Beads DNA Purification and Recovery Kit for selective recovery of DNA fragments. When different sizes of DNA fragments are required, the amount of magnetic beads used is different, please refer to the attached table for the specific amount of magnetic beads used.(If using other brands of magnetic beads, you need to figure out the optimal amount of magnetic beads by yourself).Note: Amplification products can also be fragment length sorted and purified using the Gum Recovery Kit. If there is no special requirement for library length distribution, amplification products can also be purified directly from DNA fragments without selective recovery of DNA fragments as described on page 4 of the manual.1. CMPure should be equilibrated at room temperature for 30 min after shaking and mixing before use.2. Transfer the PCR products to a 1.5 ml centrifuge tube, rehydrate to 100 µl, add several volumes of magnetic beads equilibrated to room temperature, vortex for 5 seconds, and let stand at room temperature for 5 minutes.3. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant until the solution is clear, and carefully aspirate the supernatant and transfer it to a new 1.5 ml centrifuge tube.Note: Do not discard the top clear.4. Add several volumes of magnetic beads to the supernatant, vortex and shake for 5 seconds, then let stand at room temperature for 5 minutes.5. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant until the solution is clear, carefully aspirate the supernatant and discard it, avoiding contact with the beads that have bound the target DNA.Note: Do not discard the beads.6. Continue to keep the centrifuge tube fixed on a magnetic rack and add 200 µl of freshly prepared 80% ethanol to the tube and allow to stand at room temperature for 30 seconds, carefully discarding the supernatant.Note: When adding ethanol, the liquid must not be blown directly onto the beads.7. Repeat step 6 once.8. Keep the centrifuge tube fixed on a magnetic rack and leave to dry at room temperature until the surface of the beads is slightly cracked, add 20 µl of ddH2O to solubilize.Note: Do not over-dry the beads as this may affect the elution efficiency.9. Remove the tube from the magnetic rack, vortex to completely resuspend the beads, and allow to stand at room temperature for 5 minutes. Centrifuge briefly, place the tube on the magnetic rack until the solution is clear, and transfer the supernatant solution to a new tube. Table: Suggested amount of magnetic beads for different segment selection recoveryLibrary DNA fragment purificationWe recommend the use of the Kangwei Century Magnetic Bead Method DNA Purification and Recovery Kit.1. CMPure should be equilibrated at room temperature for 30 min after shaking and mixing before use.2. 50 µl of magnetic beads equilibrated to room temperature were added to the PCR product, vortexed and shaken for 5 seconds, and then left to stand at room temperature for 5 minutes.3. Centrifuge briefly, place the tube on a magnetic rack to separate the beads from the supernatant solution until the solution is clear (approximately 3-5 minutes), carefully aspirate the supernatant and discard it, avoiding contact with the beads that have bound the target DNA. Note: Do not discard the beads.4. Continue to keep the centrifuge tube fixed on a magnetic rack and add 200 µl of freshly prepared 80% ethanol to the centrifuge tube and allow to stand at room temperature for 30 seconds, carefully discarding the supernatant.Note: When adding ethanol, the liquid must not be blown directly onto the beads.5. Repeat step 4.6. Keep the centrifuge tube fixed on a magnetic rack and leave to dry at room temperature until the surface of the beads is slightly cracked, add 25 µl of ddH2O to solubilize.Note: Do not over-dry the beads as this may affect the elution efficiency.7. Remove the tube from the magnetic rack, vortex to completely resuspend the beads, and allow to stand at room temperature for 5 minutes. Centrifuge briefly, place the tube on the magnetic rack until the solution is clear, and transfer the supernatant solution to a new tube. Library quality controlDetermination of library concentrationIn order to obtain high-quality sequencing results, accurate quantification of DNA libraries is required, and the first recommendation is to use Real-timePCR methods are used for absolute quantification of DNA libraries. Additionally, fluorescent dye methods such as the Qubit method or the fluorescent dye picogreen method can be used; do not use quantification methods based on absorbance measurements here. The following approximate formula can be used to convert the molar concentration of the DNA library.Library fragment distributionThe prepared DNA libraries can be detected by agarose gel electrophoresis or Agilent 2100 Bioanalyzer.Range of segment length distributions... Read More | Product introduction：This kit uses an improved SDS alkaline lysis method combined with DNA preparation membrane to selectively adsorb DNA to achieve the purpose of rapid purification of plasmid DNA. It is suitable for extracting up to 100u of high-purity plasmid DNA from 30-100 ml of Product introduction：This kit uses an improved SDS alkaline lysis method combined with DNA preparation membrane to selectively adsorb DNA to achieve the purpose of rapid purification of plasmid DNA. It is suitable for extracting up to 100u of high-purity plasmid DNA from 30-100 ml of bacterial culture for sequencing, in vitro transcription and translation, restriction enzyme digestion, bacterial transformation and other molecular biology experiments.Scope of application：Nucleic acid extraction and purification... Read More | This reagent kit uses an adsorption column that can specifically bind to viral RNA and a unique buffer system, suitable for isolating viral RNA from cell-free body fluids such as serum, plasma, urine, cerebrospinal fluid, and cell culture supernatants. The viral RNA specifically binds to the siliconThis reagent kit uses an adsorption column that can specifically bind to viral RNA and a unique buffer system, suitable for isolating viral RNA from cell-free body fluids such as serum, plasma, urine, cerebrospinal fluid, and cell culture supernatants. The viral RNA specifically binds to the silicon substrate membrane, and pollutants flow through the membrane. Completely remove impurities such as proteins through two efficient washes, and then wash high-purity viral RNA with RNase free water or RNase Free Water provided by the reagent kit. The virus RNA extracted by this kit can be directly used for experiments such as RT-PCR, Real time RT-PCR, and Western blot analysis. R666005Component50 TStorageR666005ABuffer GL15 mLRTR666005BBuffer RW140 mLRTR666005CBuffer RW2（concentrate）11 mLRTR666005DProteinase K12.5 mgRTR666005EProteinase K Storage Buffer1.25 mLRTR666005FRNase-Free Water10 mLRTR666005GSpin Columns RS with Collection Tubes50 setsRTR666005HRNase-Free Centrifuge Tubes（1.5 mL）50 EART Self prepared reagent: anhydrous ethanol, 0.9% NaCl.Preparation and important precautions before the experiment1. Add 1.25 ml of Protein K Storage Buffer to Protein K to dissolve it and store at -20 ℃. The prepared Protein K should not be left at room temperature for a long time to avoid repeated freeze-thaw cycles, which may affect its activity.2. To prevent RNase pollution, attention should be paid to the following aspects:1) Use RNase free plastic products and gun heads to avoid cross contamination.2) Glassware should be dry baked at a high temperature of 180 ℃ for 4 hours before use, while plastic containers can be soaked in 0.5 M NaOH for 10 minutes, thoroughly rinsed with water, and then sterilized under high pressure.3) Prepare the solution using water without RNase.4) Operators should wear disposable masks and gloves, and change gloves frequently during the experiment.3. Serum or plasma should avoid repeated freeze-thaw cycles that may cause protein denaturation or precipitation, reduce viral titers, and thus affect the yield of extracted viral nucleic acids.4. Before the first use, anhydrous ethanol should be added to Buffer RW2 according to the instructions on the reagent bottle label.5. If buffer GL precipitates, it can be heated at 56 ℃ to dissolve and then placed at room temperature.6. All centrifugation steps should be carried out at room temperature unless otherwise specified, and all operation steps should be carried out quickly.Operation steps1. Take 200 at room temperature µ Add serum or plasma to a 1.5 ml centrifuge tube (self provided). Attention: Less than 200 µ 0.9% NaCl (provided by the customer) can be added to make up for it.2. Add 20 to the solution in the previous step µ Protein K, mix well.3. Add 200 µ L Buffer GL, vortex oscillation for 15 seconds. Note: Do not directly add Protein K to Buffer GL. 4. Incubate at 56 ℃ for 15 minutes, briefly centrifuge, and collect the solution on the tube wall to the bottom of the tube.5. Add 250 µ Anhydrous ethanol, vortex for 15 seconds, incubate at room temperature for 5 minutes, briefly centrifuge, and collect the solution from the tube wall to the bottom of the tube.6. Add all the solution obtained in step 5 to the Spin Columns RS that have been loaded into the collection tube. If it is not possible to add all the solution to the adsorption column at once, please transfer it in two batches, centrifuge at 12000 rpm (~13400 × g) for 1 minute, discard the waste liquid in the collection tube, and put the adsorption column back into the collection tube.7. Add 500 to the adsorption column µ Centrifuge at 12000 rpm for 1 minute, discard the waste liquid from the collection tube, and place the adsorption column back into the collection tube.8. Add 500 to the adsorption column µ Buffer RW2 (check if anhydrous ethanol is added before use), centrifuge at 12000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.9. Add 500 to the adsorption column µ Centrifuge anhydrous ethanol at 12000 rpm for 1 minute, discard the waste liquid from the collection tube, and place the adsorption column back into the collection tube. 10. Centrifuge at 12000 rpm for 3 minutes and discard the waste liquid from the collection tube. Place the adsorption column at room temperature for a few minutes to thoroughly air dry.Attention:1) The purpose of this step is to remove residual ethanol from the adsorption column, which will affect subsequent enzymatic reactions (such as enzyme digestion, PCR, etc.).2) Recommended steps: Place the adsorption column into a new 1.5 ml centrifuge tube (provided), open the tube cover, and incubate in a 56 ℃ oven for 3 minutes to thoroughly dry the membrane of the adsorption column.11. Place the adsorption column in a new RNase free centrifuge tube and add 20-50 to the middle of the adsorption column in the air µ Place RNase Free Water at room temperature for 5 minutes, centrifuge at 12000 rpm for 1 minute, collect RNA solution, and store RNA at -70 ℃ to prevent degradation.Attention:1) The volume of RNase Free Water should not be less than 20 µ l. Small volume affects the recovery rate.2) If you want to increase RNA production, you can use 20-50 µ Repeat step 11 for the new RNase Free Water.3) If you want to increase the RNA concentration, you can add the obtained solution back to the adsorption column and repeat step 11... Read More |