| Description | Lactate dehydrogenase (LDH or LD) is a stable protein present in the cytoplasm of normal cells and normally cannot pass through the cell membrane. When cells are damaged, membrane permeability increases, and LDH is released extracellularly. A decrease in intracellular LDH and an increase in LDH in Lactate dehydrogenase (LDH or LD) is a stable protein present in the cytoplasm of normal cells and normally cannot pass through the cell membrane. When cells are damaged, membrane permeability increases, and LDH is released extracellularly. A decrease in intracellular LDH and an increase in LDH in the culture medium occur. Measuring the LDH activity in the culture medium or the LDH leakage rate can reflect drug-induced cytotoxicity. LDH belongs to the oxidoreductase family and can reversibly catalyze the redox reaction between lactate (L) and pyruvate (P). The reaction formula is: Lactate + NAD⁺ → Pyruvate + NADH + H⁺, where L → P is the forward reaction and P → L is the reverse reaction. Detection Principle: Using NAD⁺ as a hydrogen acceptor, LDH catalyzes the dehydrogenation of lactate to generate pyruvate. Pyruvate then reacts with dinitrophenylhydrazine to form pyruvate dinitrophenylhydrazone, which appears brownish-red in an alkaline solution. The color intensity is proportional to the pyruvate concentration. The absorbance at 440 nm can be measured using a microplate reader. The released LDH activity during cytotoxicity or the LDH activity in other samples can be calculated using formulas. This kit can be used for routine LDH activity detection and is more commonly used for cytotoxicity assays using LDH release as an indicator.This kit is for scientific research use only and is not intended for clinical diagnosis or other purposes.L1501786Component100T500TStorageL1501786ALDH Assay Buffer3 mL15 mL2-8℃. Store in the dark.L1501786BNAD1EA2EA-20℃L1501786CPhenylhydrazine Color Solution3 mL15 mL2-8℃. Store in the dark.L1501786DAlkaline Color Solution10 mL50 mLRT.L1501786ELDH Releasing Agent (10X)2 mL10 mLRT.User-Prepared Instruments and Reagents1. 96-well plate cultured test and control group cell samples, sterile PBS, culture medium, distilled water.2. Microplate centrifuge, 96-well plate or centrifuge, centrifuge tubes, incubator or water bath, microplate reader.Experimental Procedure1. Sample Preparation1.1 LDH Release AssaySeed an appropriate number of cells into a 96-well culture plate based on cell size and growth rate, so that the cell density does not exceed 90% confluency at the time of detection.Aspirate the culture medium, wash once with PBS, add fresh culture medium.Set up corresponding control groups according to experimental needs:Background Blank Control Well A: Culture medium without cells.Sample Control Well B: Control cells without drug treatment.Maximum Enzyme Activity Control Well C: Lysed samples from untreated cells.Drug-treated Sample Well D: Cells treated with the drug.Continue cultivation.Before detection, take out the cell culture plate. Add LDH Releasing Agent (10X) to the "Maximum Enzyme Activity Control Well C" at a volume equal to 10% of the original culture medium volume. Mix thoroughly by pipetting up and down several times. Continue cultivation for about 1 hour.Centrifuge the cell culture plate at 400 g for 5 minutes using a microplate centrifuge.Aspirate 5 µL of supernatant from each well and transfer it to the corresponding wells of a new 96-well plate for subsequent LDH detection.1.2 Cytotoxicity and Cell Proliferation Assay for Intracellular Total LDHSeed an appropriate number of cells into a 96-well culture plate based on cell size and growth rate, so that the cell density does not exceed 90% confluency at the time of detection.Treat with different drugs and set up appropriate controls.Centrifuge the cell culture plate at 400 g for 5 minutes using a microplate centrifuge.Aspirate the culture medium.Add 150 µL of LDH Releasing Agent diluted 10-fold with PBS. Shake the plate to mix thoroughly. Continue cultivation for about 1 hour.Centrifuge the cell culture plate at 400 g for 5 minutes using a microplate centrifuge.Aspirate 5 µL of supernatant from each well and transfer it to the corresponding wells of a new 96-well plate for subsequent cytotoxicity detection.1.3 Protein Concentration DeterminationAfter sample preparation, the protein concentration can be determined using a BCA Protein Assay Kit (Aladdin B665595 BCA Protein Quantification Kit or R1491648 Ready-to-Use BCA Protein Quantification Kit are recommended) to facilitate subsequent calculation of LDH content per unit protein weight in tissues or cells.2. Preparation of NAD SolutionTake one vial of NAD (powder) and dissolve it in 1.5 mL of deionized water.3. LDH Enzymatic ReactionAdd solutions sequentially according to the table below, taking care to avoid bubbles. If the enzyme activity in the sample is too high, reduce the sample volume or dilute appropriately before assay.Reagent (µL)Volume (µL)Test Sample (supernatant)5LDH Assay Buffer25NAD Solution5 Mix well, incubate at 37°C for 15 min. Phenylhydrazine Color Solution25 Mix well, incubate at 37°C for 15 min. Alkaline Color Solution100Distilled Water150 4. LDH Measurement Mix well and let stand at room temperature for 5 minutes. Measure the absorbance of each well at 440 nm using a microplate reader. 5. Result Calculation Cytotoxicity or Mortality Rate (%) = (A D - A B ) / (A C - A B ) × 100% If the absorbance value A γ of a known concentration *c* of an LDH enzyme standard and the absorbance value A γ0 of the standard blank control are measured simultaneously, the enzyme activity in the sample can be roughly calculated:LDH Activity in Test Sample (mU/mL) = (A B - A A ) / (A γ - A γ0 ) × *c* For accurate calculation of the absolute LDH enzyme activity in the sample, use a self-prepared LDH standard to plot a standard curve with the measured absorbance values. The enzyme activity of the sample can be calculated using the formula derived from the standard curve. Where: A A = Absorbance of Background Blank Control Well A A B = Absorbance of Sample Control Well B A C = Absorbance of Maximum Enzyme Activity Control Well C A D = Absorbance of Drug-treated Sample Well D 6. Results and Analysis The cytotoxicity of drugs or toxicants can be determined by directly comparing the LDH activity in each well. Higher LDH activity indicates higher cell membrane permeability and more severe cell damage.Precautions1. Use serum-free or low-serum concentration culture medium when culturing cells to exclude serum interference; otherwise, deviations may occur.2. EDTA inhibits LDH. Avoid using or thoroughly remove reagents containing EDTA during operation.3. Measure LDH as soon as possible after collection. If the collected cell culture medium is stored for too long, LDH activity may decrease.4. Use solutions prepared at the same time for the same batch of experiments. The volume of solutions used and the reaction time should be consistent.5. In the enzymatic reaction, the recommended supernatant sample volume is 2.5-10 µL. If the enzyme activity in the sample is too high, reduce the sample volume or dilute appropriately before assay.6. Measurement should be completed within 15 minutes after color development.7. The Alkaline Color Solution is somewhat corrosive; handle with care.8. Use reagents promptly after opening to avoid affecting subsequent experimental results.9. For your safety and health, please wear a lab coat and disposable gloves during operation... Read More | Format:2-ComponentEnzyme:Horseradish peroxidase | DescriptionThe plasma protein lecithin:cholesterol acyltransferase (LCAT) catalyzes the transfer of an acyl group from the sn2 position of phosphatidylcholine to the 3-hydroxyl group of cholesterol forming cholesteryl ester. This activity occurs on the surface of high density lipoprotein (HDL) and DescriptionThe plasma protein lecithin:cholesterol acyltransferase (LCAT) catalyzes the transfer of an acyl group from the sn2 position of phosphatidylcholine to the 3-hydroxyl group of cholesterol forming cholesteryl ester. This activity occurs on the surface of high density lipoprotein (HDL) and the cholesteryl esters formed by LCAT are incorporated into the core of HDL.Preparation instructionsSuitable for high-throughput screening, mechanism of action studies and structureactivity relationship (SAR) work of LCAT in plasma and serumPrincipleThe LCFC-LCAT Acyltransferase Activity Assay is a fluorometric assay useful for measuring the acyltransferase activity of LCAT in serum or plasma. The method detects changes in LCAT free cholesterol (LCFC) levels in the sample without the use of c... Read More | Products contentProducts IntroductionThe Single Cell Whole Genome Amplification Kit can be used as a template for whole genome amplification of single cells or micro samples. The total time for single-cell amplification is about 3 hours, and 2-5 µg of genomic DNA, with a size of 200-1500 bp, Products contentProducts IntroductionThe Single Cell Whole Genome Amplification Kit can be used as a template for whole genome amplification of single cells or micro samples. The total time for single-cell amplification is about 3 hours, and 2-5 µg of genomic DNA, with a size of 200-1500 bp, can be obtained after lysis, pre-amplification and amplification. The amplified product can be widely used in second-generation sequencing, large fragment copy number variation analysis, SNP typing, qPCR analysis and gene chip analysis.Bring your own instruments and reagentsPCR instrument Reaction tubes: low adsorption tubes recommended Gun Heads: High quality filtered gun heads are recommended Microcentrifuge, vortex mixercaveat The sensitivity of this product is very high, the experimental operation should be completed in a positive pressure ultra-clean bench or clean environment, the concentration of the amplification reaction products is high, should be well isolated to avoid aerosol contamination caused by amplification products.Operation flow diagramprocedurePre-experiment preparationSingle cells were obtained by flow cytometry sorting, buffer dilution, micromanipulation and laser microdissection. It is recommended that the cells be washed prior to the experiments with a 1× PBS solution free of Mg2+ and Ca2+, taking care to ensure that the volume of PBS solution in subsequent experiments does not exceed 2 µl. take note of Since the whole experiment is carried out in the same PCR tube and the reaction volume is small, the pipette tip should not touch the liquid in the tube when adding liquid, so as to avoid taking single cells or DNA out of the reaction system; when pipetting, please add the liquid along the wall of the tube carefully and do not blow the liquid in the PCR tube; before the reaction, please centrifuge briefly to make sure that the liquid in the reaction system is mixed evenly. Thaw the cell lysate, pre-amplifier and amplifier on ice before use.cell lysis 1）Mix Cell Lysis Buffer and Cell Lysis Enzyme according to the number of reactions N, shake to mix, centrifuge briefly and set aside.2）Mix single cells with the cell lysis mix in a PCR tube and run the following program.2. Pre-amplification reaction1）Mix Cell Lysis Buffer and Cell Lysis Enzyme according to the number of reactions N, shake to mix, centrifuge briefly and set aside.2）Add 5 µl of pre-amplification mix to 10 µl of lysis reaction product from the previous step and run the following program. 3. Amplification reaction1）Mix Amplification Buffer and Amp Enzyme Mix according to the number of reactions N, mix with shaking, centrifuge briefly and set aside.2）Add 60 µl of amplification mix to 15 µl of pre-amplification reaction product from the previous step and run the following program.Note: The number of cycles can be adjusted as needed, 14 cycles are recommended for single cells obtained by flow sorting, etc.Amplification product detection 1. Agarose gel electrophoresis 5 µl of the amplified product was subjected to agarose gel electrophoresis (1% agarose gel, 110 V, 25-35 min), and the amplified product was 200-1500 bp in size. 2. Quantitative Amplification products were subjected to magnetic bead or column purification, and purified products were quantified using Qubit with a final yield of 2-5 µg... Read More | This reagent kit is specially developed for one-step RT-PCR experiments. Reverse transcription and PCR are carried out in the same reaction system, without the need to add reagents or open the tube cap during the reaction process, which improves detection sensitivity and experimental efficiency This reagent kit is specially developed for one-step RT-PCR experiments. Reverse transcription and PCR are carried out in the same reaction system, without the need to add reagents or open the tube cap during the reaction process, which improves detection sensitivity and experimental efficiency while avoiding contamination. This kit includes a brand new high-efficiency reverse transcriptase, a fast hot start DNA polymerase, as well as reaction buffer suitable for reverse transcription and PCR amplification, and other components necessary for the experiment. The loss of activity of SuperRT reverse transcriptase RNase H reduces RNA degradation in reverse transcription reactions. This reverse enzyme has high reverse transcription efficiency and can perform good reverse transcription reactions on a small amount of RNA templates. The rapid hot start DNA polymerase used in PCR reaction has excellent performance of high amplification efficiency, strong specificity, and fast extension speed. The unique buffering system maximizes the efficiency of both reverse transcriptase and polymerase. The target product amplified using this reagent kit has an A base attached to the 3 'end, which can be directly used for T/A cloning.S665660Component100 TStorageS665660ASuperRT OneStep EnzymeMix50 µL-20℃. Avoid freeze/thaw cycle.S665660B2×SuperRT OneStep Buffer1.4 mL-20℃. Avoid freeze/thaw cycle.S665660CRNase-Free Water1.5 mL-20℃. Avoid freeze/thaw cycle. Notes:1. During the operation process, RNase contamination should be avoided to prevent RNA degradation or cross contamination during experiments. It is recommended to perform RNA operations in specialized areas, use specialized instruments and consumables, and have operators wear masks and disposable gloves, and frequently change gloves.2. Disposable plastic containers should be used as much as possible for experiments. If glass containers are used, they should be treated with a 0.1% DEPC (diethyl pyrocarbonate) aqueous solution at 37 ℃ for 12 hours, and sterilized under high pressure at 120 ℃ for 30 minutes before use. Alternatively, glass containers should be sterilized under dry heat at 180 ℃ for 60 minutes before use. The sterile water used in the experiment should be treated with 0.1% DEPC and then subjected to high-pressure sterilization.3. All reagents in this reagent kit should be gently mixed upside down before use, avoiding foaming as much as possible, and used after brief centrifugation. The enzymes involved should be returned to -20 ℃ as soon as possible after use to avoid repeated freeze-thaw cycles.4. This reagent kit must use specific primers, and the selection of primers can be based on specific experiments. The quality of primer design directly affects the results of RT-PCR reactions. When designing primers, factors such as GC content, primer length, primer position, and the secondary structure of PCR products need to be considered. It is recommended to use professional primer design software.Usage:1. Dissolve the RNA template, primers, OneStep RT-PCR Buffer, SuperRT OneStep RT-PCR EnzymeMix, and RNase Free Water and place them on ice for later use.2. Prepare the reaction system according to the following table: Reagent 25 µlReaction system Final concentration 2×SuperRT OneStep Buffer 12.5 µl 1× Forward Primer，10 µM 1 µl 0.4 µM Reverse Primer，10 µM 1 µl 0.4 µM SuperRT OneStep EnzymeMix 0.5 µl / RNA Template X µl 1 pg – 1 µg RNase-Free Water up to 25 µl / Attention: The primer concentration should be between 0.1 and 1.0 as the final concentration µ M serves as a reference for setting the range. In the case of low amplification efficiency, the concentration of primers can be increased; When non-specific reactions occur, the primer concentration can be reduced to optimize the reaction system.3. Vortex and shake well, centrifuge briefly, and collect the solution to the bottom of the tube.4. Preheat the thermal cycler to 45 ℃, place the PCR tube in the thermal cycler, and perform RT-PCR reaction.Reaction conditions: Step Temperature Time / Reverse transcription 45℃ 30 min / PCR pre denaturation 95℃ 2 min Denaturation 94℃ 30 s 30-40 cycles Anneal 55-65℃ 30 s 30-40 cycles Extend 72℃ 30 s 30-40 cycles Finally extended 72℃ 5 min /Attention:1) In general PCR experiments, the annealing temperature is 5 ℃ lower than the melting temperature Tm of the amplification primer, and the annealing time is generally 20-30 seconds. If the ideal amplification efficiency cannot be achieved, the annealing temperature should be appropriately reduced; When non-specific reactions occur, increase the annealing temperature to optimize the reaction conditions.2) The extension time is set based on the size of the amplified fragments, and the DNA Polymerase amplification efficiency contained in this product is 1 kb/30s.3) The number of cycles can be set based on the downstream application of the amplification product. Too few cycles, insufficient amplification; Multiple cycles increase the probability of mismatches and result in severe non-specific backgrounds. Therefore, while ensuring product yield, the number of cycles should be minimized as much as possible.5. After the reaction is complete, take 5 µ l of the reaction product, add an appropriate amount of loading buffer, and perform electrophoresis detection results... Read More |