| 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 | Product Descriptionalpha-L-fucoside fucohydrolase, alpha-L-fucosidase, alpha-(1-3,4) fucosidaseAlpha (1-3,4) Fucosidase The enzyme is very efficient and recognises α1-3,4 fucosylated glycans (e.g. Lewis X/A epitopes, including their sialylated counterparts) and hydrolyses terminal α1-3 andProduct Descriptionalpha-L-fucoside fucohydrolase, alpha-L-fucosidase, alpha-(1-3,4) fucosidaseAlpha (1-3,4) Fucosidase The enzyme is very efficient and recognises α1-3,4 fucosylated glycans (e.g. Lewis X/A epitopes, including their sialylated counterparts) and hydrolyses terminal α1-3 and α1-4 fucosyl linkages in these substrates without the need to remove sialic acid moieties.For removing core fucose linked α-(1-6) to the core GlcNAc of a GlcNAc-GlcNAc disaccharide structure we recommend our Alpha-(1-6) Fucosidase.• Non-sialidase dependant hydrolysis of antennary fucose moieties• Effective on both glycopeptides and free glycans• Highly specific (α1-3,4 fucosylated glycans)• Kit includes enzyme plus reaction buffer.• Sufficient for up to 50 samplesα(1-3,4) Fucosidase is useful for:nbsp;nbsp;Fucose linkage determinationnbsp;nbsp;Deglycosylating glycoproteins with Lewis structuresContentsAlpha-(1-3,4)-Fucosidase – 200 mM citrate buffer pH 6 containing 250 mM NaCl5x Reaction Buffer – 250 mM sodium phosphate pH 6... Read More | Inquire | Product content:E665636Component50 TStorageE665636ABuffer P115 mLRTE665636BBuffer P215 mLRTE665636CBuffer E315 mLRTE665636DBuffer PS15 mLRTE665636EBuffer PW (concentrate)10 mLRTE665636FEndo-Free Buffer EB10 mLRTE665636GRNase A (10 mg/mL)150 µLRTE665636HEndo-Remover FMwith Collection Tubes50 Product content:E665636Component50 TStorageE665636ABuffer P115 mLRTE665636BBuffer P215 mLRTE665636CBuffer E315 mLRTE665636DBuffer PS15 mLRTE665636EBuffer PW (concentrate)10 mLRTE665636FEndo-Free Buffer EB10 mLRTE665636GRNase A (10 mg/mL)150 µLRTE665636HEndo-Remover FMwith Collection Tubes50 EARTE665636ISpin Columns DMwith Collection Tubes50 EART Product Introduction:Endotoxins are a common pollutant in plasmid extraction. Due to the high sensitivity of eukaryotic cells to endotoxins, the presence of endotoxins in plasmids can greatly reduce the transfection efficiency of eukaryotic cells. This reagent kit provides a simple, fast, and efficient new method for extracting endotoxin free plasmids. The extracted plasmids remove endotoxins to the maximum extent possible and can effectively remove contamination of genomic DNA, RNA, proteins, etc. The operation is simple and convenient. This reagent kit is suitable for extracting 1-5mL of bacterial solution. On the basis of alkaline lysis of cells, it efficiently and specifically binds plasmid DNA through a new silicon-based membrane. Each adsorption column can adsorb up to 40% µ The plasmid DNA of g is effectively removed using a special buffer system and endotoxin removal filter column, effectively removing impurities such as endotoxins and proteins. The plasmid obtained from this kit has high purity and stable quality, making it particularly suitable for cell transfection. It can also be used for downstream experiments such as DNA sequencing, PCR, PCR based mutations, in vitro transcription, transformed bacteria, and endonuclease digestion.Self prepared reagents: anhydrous ethanol, isopropanol.Preparation and important precautions before the experiment：1. All components can be stably stored for 1 year in a dry, room temperature (15-30 ℃) environment. The adsorption column can be stored for a longer time at 2-8 ℃. Buffer P1 with RNase A added can be stably stored for 6 months at 2-8 ℃. 2. Before the first use, add all RNase A solution to Buffer P1, mix well, and store at 2-8 ℃. Before use, let it sit at room temperature for a period of time. After returning to room temperature, use.3.Before the first use, anhydrous ethanol should be added to the Buffer PW according to the instructions on the reagent bottle label.4. Before use, please check if there is any crystallization or precipitation in Buffer P2 and Buffer E3. If there is any crystallization or precipitation, you can take a water bath at 37 ℃ for a few minutes to restore clarity.5. Be careful not to come into direct contact with Buffer P2 and Buffer E3, and immediately cover them tightly after use.6.The amount and purity of plasmid extraction are related to factors such as bacterial culture concentration, strain type, plasmid size, and plasmid copy number.Operation steps：1. Take 1-5 mL of overnight cultured bacterial solution and add it to a centrifuge tube (provided). Centrifuge at 13000 rpm (~16200 × g) for 30 seconds to collect bacteria, and try to discard all the supernatant as much as possible.2. Add 250 to the centrifuge tube containing bacterial sediment µ L Buffer P1 (please check if RNase A has been added first), mix thoroughly with a pipette or vortex oscillator, and suspend bacterial precipitation.Attention: If the bacterial blocks are not thoroughly mixed, it will affect the cracking effect, resulting in low extraction amount and purity.3. Add 250 to the centrifuge tube µ L Buffer P2, gently invert and mix 8-10 times, allowing the bacterial cells to fully lyse. Leave at room temperature for 3-5 minutes. At this point, the solution should become clear and viscous.Attention: Mix gently and do not shake vigorously to avoid interrupting genomic DNA and mixing genomic DNA fragments in the extracted plasmid. If the solution does not become clear, it indicates that the bacterial count may be too high and the lysis may not be complete. The bacterial count should be reduced.4. Add 250 to the centrifuge tube µ L Buffer E3, immediately invert and mix 8-10 times until white flocculent precipitates appear. Let it stand at room temperature for 5 minutes. Centrifuge at 13000 rpm for 5 minutes, extract the supernatant, and add it to a filter column (Endo Remove FM). Centrifuge at 13000 rpm for 1 minute to filter, and collect the filtrate in a centrifuge tube (self provided).Attention: After adding Buffer E3, it should be mixed evenly immediately to avoid local precipitation. 5. Add 225 to the filtrate µ Mix L isopropanol upside down.6. Column balance: Add 200 to the spin columns DM that have been loaded into the collection tube µ L Buffer PS, centrifuge at 13000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.7. Transfer the mixed solution of filtrate and isopropanol from step 5 to an equilibrium adsorption column (already loaded into a collection tube).8.13000 rpm for 1 minute, discard the waste liquid in the collection tube, and place the adsorption column back into the collection tube.Attention: The maximum volume of the adsorption column is 750 µ L. If the sample volume is greater than 750 µ L can be added in batches. 9. Add 750 to the adsorption column µ L Buffer PW (please check if anhydrous ethanol has been added first), centrifuge at 13000 rpm for 1 minute, and discard the waste liquid in the collection tube.10. Place the adsorption column back into the recovery manifold and centrifuge at 13000 rpm for 1 minute. Note: The purpose of this step is to remove residual ethanol from the adsorption column, which can affect subsequent enzymatic reactions (such as enzyme digestion, PCR, etc.).11. Place the adsorption column in a new collection tube and add 50-100 to the middle of the adsorption membrane µ L Endo Free Buffer EB, let it stand at room temperature for 2-5 minutes, centrifuge at 13000 rpm for 2 minutes, and collect the plasmid solution into a centrifuge tube- Store the plasmid at 20 ℃.Note: 1) To increase the efficiency of plasmid recovery, the obtained solution can be added back to the adsorption column, left at room temperature for 2-5 minutes, centrifuged at 13000 rpm for 2 minutes, and collected into a centrifuge tube.2) When the plasmid copy number is low or>10 kb, preheating the Endo Free Buffer EB in a water bath at 65-70 ℃ can increase the extraction efficiency... Read More | Product introduction：Used to isolate lymphocytes from human organsMatters needing attention：1. samples, reagents and experimental environment in the whole process shall be carried out at 20 ± 2 ℃. In order to obtain the best experimental results, it is best to carry out the Product introduction：Used to isolate lymphocytes from human organsMatters needing attention：1. samples, reagents and experimental environment in the whole process shall be carried out at 20 ± 2 ℃. In order to obtain the best experimental results, it is best to carry out the experiment within 2 h of sampling. The longer the sample is stored, the worse the cell separation effect is. The separation effect is even worse after the sample is placed for more than 6 h, or even cannot achieve the purpose of separation. 2. in this experiment, it is better not to use plastic products with high polymerization materials (such as polystyrene), but use non-static, low static ionization heart tubes and glass products without alkali treatment, because the electrostatic effect will lead to cell adhesion, and the surface of alkali treated glass will become rough, which will affect the effect of cell separation. 3. aspirating too many lymphocyte layers and separation liquid layers will cause the granulocytes at the junction of separation liquid to be aspirated, thus increasing the number of mixed granulocytes. 4. when the amount of separating solution is greater than that of tissue single cell suspension sample, the separation effect is better.Scope of application：Lymphocyte isolation... Read More |