| Description | Pyruvate phosphate dikinase (PPDK, EC 2.7.9.1) is a rate-limiting enzyme in the C4 pathway and Crassulacean acid metabolism (CAM) pathway. It catalyzes the three-step conversion of ATP, pyruvate, and Pi to phosphoenolpyruvate. This enzyme is primarily located in the chloroplast stroma of C4 plants Pyruvate phosphate dikinase (PPDK, EC 2.7.9.1) is a rate-limiting enzyme in the C4 pathway and Crassulacean acid metabolism (CAM) pathway. It catalyzes the three-step conversion of ATP, pyruvate, and Pi to phosphoenolpyruvate. This enzyme is primarily located in the chloroplast stroma of C4 plants and plays a crucial regulatory role in photosynthetic function.Assay Principle The reverse reaction catalyzed by PPDK converts phosphoenolpyruvate, AMP, and PPi into pyruvate, ATP, and Pi. Lactate dehydrogenase then further catalyzes the reaction of pyruvate and NADH to produce lactate and NAD+. The decrease in NADH is measured at 340 nm, and the rate of this decrease is used to calculate PPDK activity.Component50TStorageExtraction Buffer60 mL2-8℃Reagent 160 mL2-8℃Reagent 22 EA-20℃Reagent 360 µL2-8℃Note for Reagent 3: The volume is small. If the liquid is on the tube wall, briefly centrifuge before use.User-Prepared Instruments & MaterialsUV spectrophotometer, benchtop centrifuge, adjustable pipettes, 1 ml quartz cuvette, mortar, ice, and distilled water.Sample PreparationHomogenize the tissue sample in ice-cold Extraction Buffer using a mortar and pestle, using a ratio of 1:5 to 1:10 (tissue weight (g) : Extraction Buffer volume (mL)). (It is recommended to weigh about 0.1 g of tissue and add 1 mL of Extraction Buffer). Centrifuge the homogenate at 8000 g, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.Assay Procedure1. Spectrophotometer Setup: Preheat the spectrophotometer for at least 30 minutes. Set the wavelength to 340 nm. Zero the instrument with distilled water.2. Sample Measurement:2.1 Working Solution Preparation: Just before use, add one vial of Reagent 2 to 25 mL of Reagent 1 and add 12.5 µL of Reagent 3. Mix thoroughly and incubate at 37°C for 5 minutes. Any unused solution should be aliquoted and stored at -20°C. Avoid repeated freeze-thaw cycles.2.2 Reaction Setup: Add 50 µL of the sample supernatant and 950 µL of the Working Solution into a 1 mL quartz cuvette. Mix immediately and record the initial absorbance value at 340 nm (A1). After incubating at 37°C for exactly 5 minutes, record the absorbance value again (A2). Calculate ΔA = A1 - A2. PPDK Activity Calculation 1. Based on Sample Protein Concentration: Unit Definition: One unit of enzyme activity is defined as the amount that consumes 1 nmol of NADH per minute per mg of protein. Formula: PPDK Activity (nmol/min/mg prot) = [ΔA × V total_reaction ÷ (ε × d) × 10⁹] ÷ (V sample × Cpr) ÷ T = 643 × ΔA ÷ Cpr 2. Based on Sample Fresh Weight: Unit Definition: One unit of enzyme activity is defined as the amount that consumes 1 nmol of NADH per minute per gram of fresh tissue. Formula: PPDK Activity (nmol/min/g fresh weight) = [ΔA × V total_reaction ÷ (ε × d) × 10⁹] ÷ (W × V sample ÷ V total_extract ) ÷ T = 643 × ΔA ÷ WParameters Explanation: V total reaction : Total reaction volume, 1 × 10⁻³ L ε: Molar extinction coefficient of NADH, 6.22 × 10³ L/mol/cm d: Light path of the cuvette, 1 cm V sample : Volume of sample supernatant added, 0.05 mL V total extract : Total volume of extraction buffer added, 1 mL T: Reaction time, 5 min Cpr: Sample protein concentration, mg/mL W: Sample mass, g Notes It is essential to perform a preliminary assay using 2-3 samples expected to have significant activity differences before formal testing... Read More | Inquire | When apoptosis occurs, some DNA endonucleases will be activated. These endonucleases will cut off genomic DNA between nucleosomes and produce 180 bp-200 BP DNA fragments, which appear as a specific ladder pattern in agarose gel electrophoresis. When double strand or single strand breaks occurWhen apoptosis occurs, some DNA endonucleases will be activated. These endonucleases will cut off genomic DNA between nucleosomes and produce 180 bp-200 BP DNA fragments, which appear as a specific ladder pattern in agarose gel electrophoresis. When double strand or single strand breaks occur in genomic DNA, a large number of sticky 3'-oh ends will be generated, which can interact with YF under the catalysis of deoxyribonucleotide terminal transferase (TDT) ®/ CY dUTP binding can directly detect apoptotic cells by fluorescence microscopy or flow cytometry. This kind of method is called terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL). Because normal or proliferating cells have almost no DNA breaks, there is no 3'-oh formation and they can rarely be stained. TUNEL method can stain intact single apoptotic nuclei or apoptotic bodies in situ, can accurately reflect the typical biochemical and morphological characteristics of apoptosis, and can detect a very small number of apoptotic cells, so it is widely used in the study of apoptosis. This kit has a wide range of applications and can be used to detect apoptosis in frozen or paraffin sections, as well as cultured adherent cells or suspended cells. It can selectively detect apoptotic cells, but not necrotic cells or cells with DNA strand breaks caused by irradiation and drug treatment. This kit detects cell apoptosis with a short time-consuming, one-step staining reaction and can be detected after washing.Component： Instruction： Experimental materials (self provided)PBS buffer (1 x, pH~7.4). 0.2% Triton X -100 (PBS formulation). 0.1% Triton X -100 (PBS formulation, containing 5 mg/mLBSA)4% paraformaldehyde (prepared with PBS)Immunohistochemical penDewaxing solvent (paraffin section sample)Related reagents for paraffin section processingAnti fluorescence quenching and sealing agent. ddH2Oexperimental design. A. Positive control:Prepare positive control slides using DNaseI treatment. DNaseI can digest single or double stranded DNA and expose the 3 '- OH end, artificially causing cell apoptosis. One experiment per time is sufficient. (To verify if there are any issues with the experimental operation and reagent kit)B. Negative control:Use TUNEL Reaction Buffer without TdT Enzyme and replace TdT Enzyme with ddH2O. (Mainly to exclude non-specific staining caused by cell apoptosis, operational processes, and other reasons; and to adjust the exposure intensity of the shooting.)C. Experimental processing group.The experimental group operated normally according to the instructions.D. Experimental control group.The experimental group operated normally according to the instructions.Experimental steps1. Sample preparation:(1) For adherent cells or cell smearsa. Clean once with PBS.Note: If you are concerned that the cells on the cell smear may not adhere firmly, you can dry the sample to make the cells adhere more firmly.b. Fixation: Add an appropriate amount of 4% paraformaldehyde (prepared with PBS) and fix at 4 ℃ for 30 minutes. Clean twice with PBS.c. Translucency: Add an appropriate amount of 0.2% Triton X -100 (prepared with PBS) and let it penetrate at room temperature for 20 minutes. Clean twice with PBS.d. Step 2: TUNEL reaction.(2) For suspended cells or cell suspensionsa. Collect cells (3-5 x 106 cells), centrifuge at 1000 rpm for 5 minutes, and wash twice with PBS.b. Fixation: Add an appropriate amount of 4% paraformaldehyde (prepared with PBS) and resuspend the cells thoroughly. Fix at 4 ℃ for 30 minutes. Centrifuge at 2000 rpm for 5 minutes and clean twice with PBS.c. Translucency: Add an appropriate amount of 0.2% Triton X -100 (prepared with PBS) and let it penetrate at room temperature for 20 minutes. Centrifuge at 2000 rpm for 5 minutes and clean twice with PBS.d. Step 2: TUNEL reaction.(3) Paraffin tissue sectioninga. Dewaxing and hydration: Place the sliced samples sequentially in xylene I (10 min) → xylene II (10 min) → 100% ethanol I (5 min) → 100% ethanol II (5 min) → 95% ethanol (5 min) → 90% ethanol (5 min) → 80% ethanol (5 min) → 70% ethanol (5 min) → ddH2O rinse for 5 min, rinse twice.Note: Xylene is toxic and volatile. Please perform this operation in a fume hood.b. Use filter paper to dry the liquid around the sliced sample, and circle the sample contour with an immunohistochemical pen for downstream transparency and labeling.Note: If it is found that the contour circle of immunohistochemistry strokes is damaged in subsequent experimental operations, it needs to be redrawn in a timely manner.c. Transparency: Dilute 2 mg/mL of ProteinaseK solution with PBS in a ratio of 1:100 to a final concentration of 20 µ g/mL. Add 100 µ L dropwise to each sample to cover all sample areas. Incubate at 20-37 ℃ for 20 minutes.Note: Protein K can penetrate the cell membrane and nuclear membrane, allowing subsequent staining reagents to fully enter the nucleus for reaction and improve labeling efficiency. An excessively long incubation time increases the risk of tissue slices falling off the carrier film during subsequent washing steps, while a too short incubation time may result in insufficient permeability treatment and affect labeling efficiency. To obtain better results, the concentration, incubation time, and temperature of Protein K need to be optimized according to different types of tissue samples.d. Wash the slices twice with PBS, each time for 5 minutes. Use filter paper to remove excess liquid, and place the processed sample in a wet box to keep it moist.Note: Protein K must be washed thoroughly in this step, otherwise it will seriously interfere with subsequent labeling reactions.e. Step 2: TUNEL reaction.(4) Frozen tissue sectionsa. Fixation: Take out frozen sections and warm them back to room temperature. Add an appropriate amount of 4% paraformaldehyde (prepared with PBS) and fix at room temperature for 30 minutes. Wash twice with PBS for 10 minutes each time.Note: If you are concerned that formaldehyde cleaning may not be clean enough, it may affect the final dyeing effect. After formaldehyde fixation is completed, an appropriate amount of 2 mg/mL glycine can be added and washed for 10 minutes to neutralize the residual fixing solution, and then PBS cleaning can be carried out.b. Use filter paper to dry the liquid around the sliced sample, and circle the sample contour with an immunohistochemical pen for downstream transparency and labeling.Note: If it is found that the contour circle of immunohistochemistry strokes is damaged in subsequent experimental operations, it needs to be redrawn in a timely manner.c. Transparency: Dilute 2 mg/mL of ProteinaseK solution with PBS in a ratio of 1:100 to a final concentration of 20 µ g/mL. Add 100 µ L dropwise to each sample to cover all sample areas. Incubate at 20-37 ℃ for 20 minutes.Note: Protein K can penetrate the cell membrane and nuclear membrane, allowing subsequent staining reagents to fully enter the nucleus for reaction and improve labeling efficiency. An excessively long incubation time increases the risk of tissue slices falling off the carrier film during subsequent washing steps, while a too short incubation time may result in insufficient permeability treatment and affect labeling efficiency. To obtain better results, the concentration, incubation time, and temperature of Protein K need to be optimized according to different types of tissue samples.d. Wash the slices twice with PBS, each time for 5 minutes. Use filter paper to remove excess liquid, and place the processed sample in a wet box to keep it moist.Note: Protein K must be washed thoroughly in this step, otherwise it will seriously interfere with subsequent labeling reactions.e. Step 2: TUNEL reaction.(5) Positive treatment (only the positive control is subjected to this step, and other samples are directly subjected to the TUNEL reaction step)a. Dilute 10 x DNase I Buffer with ddH2O in a ratio of 1:10 to 1 x DNase I Buffer for later use.b. Drip 100 µ L of 1xDNase I Buffer onto the processed sample, covering all sample areas, and equilibrate at room temperature for 5 minutes.c. Dilute DNase I (2 U) with 1 x DNase I Buffer at a ratio of 1:100/ µ L) A working solution with a final concentration of 20 U/mL.d. Discard the buffer and add 100 µ Incubate DNase I working solution with a concentration of 20 U/mL at room temperature for 10 minutes.e. Discard DNase I working solution and clean twice with PBS.f. Step 2: TUNEL reaction.2. TUNEL reaction(1) Prepare TUNEL reaction solution (ready to use):/1 sample5sample10 sampleTdT enzyme1 µL5 µL10 µLYF®488/555/594/640 TUNEL Reaction Buffer49 µL245 µL490 µLTUNEL Total volume of reaction solution50 µL250 µL500 µL(2) For adherent cells, cell smears, or tissue sectionsa. Add 50 to each sample µ L TUNEL reaction solution, evenly cover the sample with the reaction solution. The appropriate time for dark incubation at 37 ℃ (recommended staining time for cells is 30 minutes to 1 hour, and tissue staining time is 2 hours).Note: 50 µ L TUNEL reaction solution is suitable for smear, slicing, or 96 well plates (other different well plates can adjust the volume of TUNEL reaction solution appropriately to cover cells). If the sample to be tested is a smear, slice, or in a 24 well plate, 12 well plate, or 6 well plate, anti evaporation film can be used, or self sealing bags or other appropriate materials can be used to cut circular plastic sheets slightly smaller than the holes. After adding TUNEL reaction solution dropwise, cover the sample to prevent the evaporation of TUNEL reaction solution and make the TUNEL reaction solution evenly cover the sample.b. Discard the TUNEL reaction solution, wash twice with PBS, and then wash three times with 0.1% Triton X -100 (PBS preparation, containing 5 mg/mL BSA) for 5 minutes each time. This way, free unreacted markers can be removed cleanly.c. (Optional) Add an appropriate concentration of 5 to each sample µ DAPI staining solution with a concentration of g/mL, incubated at room temperature in dark for 5 minutes. After staining, discard DAPI staining solution and wash twice with PBS for 5 minutes each time.d. (Optional) Slice sealing: Add 50 drops to each sample µ L anti fluorescence quenching sealing agent (anti fluorescence quenching sealing agent may not be suitable for certain dyes, it is recommended to conduct pre experimental testing for compatibility before the experiment), cover the cover glass, gently tap the cover glass with the blunt end of tweezers to remove bubbles and ensure complete sealing.e. Use filter paper to remove excess liquid and add 100 to the sample area µ Keep the sample moist with PBS and immediately observe under a fluorescence microscope.(3) For suspended cells or cell suspensionsa. Add 50 to each sample tube µ Gently resuspend cells in LTUNEL reaction solution and incubate at 37 ℃ in the dark for 30-1 hour. Gently resuspend cells with a micropipette every 15 minutes.b. Centrifuge at 2000 rpm for 5 minutes, discard TUNEL reaction solution, and wash twice with 0.1% Triton X -100 (PBS preparation, containing 5 mg/mLBSA) for 5 minutes each time. This way, free unreacted markers can be removed cleanly.c. Add 100 to each sample tube µ L concentration is 5 µ DAPI staining solution with a concentration of g/mL, incubated at room temperature in dark for 5 minutes.d. Join 400 µ L PBS resuspended cells and immediately detected with a flow cytometer or observed under a fluorescence microscope after smearing.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. when the staining background is heavy or non-specific staining is obvious, the staining time can be appropriately reduced. 3. it is recommended to add negative control and positive control groups during the experiment. 4. please wear mask and gloves when using component A. if it contacts the skin, please wash it with plenty of water immediately. 5. fluorescent dyes have quenching problems. Please try to avoid light to slow down fluorescence quenching. 6. for your safety and health, please wear experimental clothes and disposable gloves.Product parameters：490/515 nm；Scope of application：Late apoptosis detection, TUNEL Kit... Read More | Inquire | DescriptionWhite LED Array for Photo KitAlysis high-throughput screening platform. For use with Photo KitAlysis Starter Kit (Z742612). User guide is provided in the below hyperlink.Photo KitAlysis Operating InstructionsFeatures:Designed and tested by synthetic chemists.Controller provides repeatableDescriptionWhite LED Array for Photo KitAlysis high-throughput screening platform. For use with Photo KitAlysis Starter Kit (Z742612). User guide is provided in the below hyperlink.Photo KitAlysis Operating InstructionsFeatures:Designed and tested by synthetic chemists.Controller provides repeatable milliamp selection for photon intensity (sold seperately)0-30 mA variable LED outputNon-magnetic LED baseChemically resistant LED coverPTFE coated cablingPhoto Kitalysis Starter Kitrequired for operation (sold separately). Best when used withKitAlysis Benchtop Inertion Box(sold separately)... Read More |