| Description | Phosphoenolpyruvate Carboxykinase (PEPCK, EC 4.1.1.32) is widely present in animals, plants, microorganisms, and cells. It catalyzes the conversion of oxaloacetate to phosphoenolpyruvate and is a key regulatory enzyme in the gluconeogenesis pathway.Assay PrinciplePEPCK catalyzes the conversion of Phosphoenolpyruvate Carboxykinase (PEPCK, EC 4.1.1.32) is widely present in animals, plants, microorganisms, and cells. It catalyzes the conversion of oxaloacetate to phosphoenolpyruvate and is a key regulatory enzyme in the gluconeogenesis pathway.Assay PrinciplePEPCK catalyzes the conversion of Oxaloacetate to Phosphoenolpyruvate and CO₂. Pyruvate Kinase and Lactate Dehydrogenase subsequently catalyze the sequential oxidation of NADH to NAD⁺. The rate of decrease in NADH absorbance at 340 nm is measured, which reflects PEPCK activity.Component100TStorageExtraction Buffer100 mL2-8℃Reagent 118 mL2-8℃Reagent 216.5 µL2-8℃Reagent 31EA-20℃Reagent 41EA-20℃Required Materials and Equipment (Not Provided)Spectrophotometer / Microplate reader, benchtop centrifuge, adjustable pipettes, micro quartz cuvette / 96-well plate, mortar and pestle, ice, and distilled water.Sample Preparation:1.Bacteria or Cultured Cells:Collect cells by centrifugation and discard the supernatant.Add Extraction Buffer at a ratio of 1 ml per 5-10 million cells (e.g., 1 ml for 5 million cells).Sonicate on ice (20% power or 200W, pulse 3s on/10s off, repeat 30 times).Centrifuge at 8000 g, 4°C for 10 min. Collect the supernatant and keep it on ice for assay.2.Tissues:Homogenize tissue on ice in Extraction Buffer at a ratio of 1:5-10 (w/v) (e.g., 0.1 g tissue in 1 ml buffer).Centrifuge at 8000 g, 4°C for 10 min. Collect the supernatant and keep it on ice for assay.3.Serum (or Plasma) Samples:Assay directly.Assay Procedure:1.Preheat the spectrophotometer or microplate reader for at least 30 minutes. Set the wavelength to 340 nm. Zero the instrument with distilled water.2.Preparation of Working Solution: Just before use, transfer and dissolve Reagent 2 and Reagent 3 into Reagent 1. Mix well. Aliquot and store any unused portions at -20°C. Avoid repeated freeze-thaw cycles.3.Preparation of Reagent 4: Just before use, dissolve the contents of the vial in 1 ml of distilled water. Mix well. Aliquot and store any unused portions at -20°C. Avoid repeated freeze-thaw cycles.4.Pre-warm the Working Solution and dissolved Reagent 4 at 37°C (for mammalian samples) or 25°C (for other species) for 5 minutes.5.In a micro quartz cuvette or a well of a 96-well plate, add:10 µl sample10 µl dissolved Reagent 4180 µl pre-warmed Working SolutionMix immediately and record the initial absorbance (A₁) at 340 nm. Record the absorbance again (A₂) after exactly 1 minute. Calculate ΔA = A₁ - A₂.Note: For this kit, if ΔA is greater than 0.1, dilute the sample with Extraction Buffer by an appropriate factor (account for this dilution factor 'n' in the calculations) so that ΔA is less than 0.1 to improve detection sensitivity.PEPCK Activity Calculation:1. Calculation for Micro Quartz Cuvette (d = 1.0 cm)General Parameters for Cuvette:Vₜₒₜₐₗ (Total reaction volume) = 0.0002 L (200 µL)ε (NADH molar extinction coefficient) = 6220 L/mol/cmd (Cuvette light path) = 1.0 cmVₛₐₘₚₗₑ (Sample volume in reaction) = 0.01 mL (10 µL)T (Reaction time) = 1 minVₛₐₘₚₗₑₜₒₜₐₗ (Total extract volume) = 1 mL (for tissues/cells)Cpr (Sample protein concentration, mg/mL)W (Sample mass, g)500 (Cell/Bacteria count in millions for example calculation: 5 million)a. For Serum (Plasma):Definition: One unit of activity is defined as the amount of enzyme that consumes 1 nmol of NADH per minute per ml of serum.Calculation:PEPCK Activity (nmol/min/ml) = [ΔA × Vₜₒₜₐₗ ÷ (ε × d) × 10⁹] ÷ Vₛₐₘₚₗₑ ÷ TSimplified Formula: PEPCK (nmol/min/ml) = 3215 × ΔAb. For Tissues, Bacteria, or Cells:Based on Sample Protein Concentration:Definition: One unit of activity is defined as the amount of enzyme that consumes 1 nmol of NADH per minute per mg of protein.Calculation:PEPCK Activity (nmol/min/mg prot) = [ΔA × Vₜₒₜₐₗ ÷ (ε × d) × 10⁹] ÷ (Vₛₐₘₚₗₑ × Cpr) ÷ TSimplified Formula: PEPCK (nmol/min/mg prot) = 3215 × ΔA ÷ CprBased on Sample Fresh Weight:Definition: One unit of activity is defined as the amount of enzyme that consumes 1 nmol of NADH per minute per gram of fresh tissue.Calculation:PEPCK Activity (nmol/min/g fresh weight) = [ΔA × Vₜₒₜₐₗ ÷ (ε × d) × 10⁹] ÷ (W × Vₛₐₘₚₗₑ / Vₛₐₘₚₗₑₜₒₜₐₗ) ÷ TSimplified Formula: PEPCK (nmol/min/g fresh weight) = 3215 × ΔA ÷ WBased on Bacterial or Cell Density:Definition: One unit of activity is defined as the amount of enzyme that consumes 1 nmol of NADH per minute per 10⁴ cells.Calculation (example for 5 million cells in 1 ml extract):PEPCK Activity (nmol/min/10⁴ cell) = [ΔA × Vₜₒₜₐₗ ÷ (ε × d) × 10⁹] ÷ (500 × Vₛₐₘₚₗₑ / Vₛₐₘₚₗₑₜₒₜₐₗ) ÷ TSimplified Formula: PEPCK (nmol/min/10⁴ cell) = 6.43 × ΔA2. Calculation for 96-Well Plate (d = 0.5 cm)General Parameters for 96-Well Plate:(All parameters remain the same except for the light path 'd')d (96-well plate light path) = 0.5 cma. For Serum (Plasma):Simplified Formula: PEPCK (nmol/min/ml) = 6430 × ΔAb. For Tissues, Bacteria, or Cells:Based on Sample Protein Concentration:Simplified Formula: PEPCK (nmol/min/mg prot) = 6430 × ΔA ÷ CprBased on Sample Fresh Weight:Simplified Formula: PEPCK (nmol/min/g fresh weight) = 6430 × ΔA ÷ WBased on Bacterial or Cell Density:Simplified Formula: PEPCK (nmol/min/10⁴ cell) = 12.86 × ΔAPrecautionsBefore formal assay, it is essential to perform a pilot test with 2-3 samples expected to have significant differences in activity... Read More | Inquire | Product introduction： The MA qPCR live bacteria detection kit provides an effective means for detecting bacterial activity. The kit provides a mixture of PMA dye and qPCR based on SYBR Green dye. The optimal amount of dye and the number of samples that can be treated may vary depending on theProduct introduction： The MA qPCR live bacteria detection kit provides an effective means for detecting bacterial activity. The kit provides a mixture of PMA dye and qPCR based on SYBR Green dye. The optimal amount of dye and the number of samples that can be treated may vary depending on the type of sample. PMA is a high-affinity DNA-binding dye, especially with double-stranded DNA. The dye itself has weak fluorescence, but it can emit brighter fluorescence after binding to nucleic acids. PMA is impermeable to cell membranes, so it can selectively modify the DNA of dead cells with damaged membranes. After the PMA-modified DNA is photolyzed by blue light ( ~ 464 nm ), the photoreactive azide group on the PMA is converted into a highly reactive nitrene radical, which reacts with any hydrocarbon near the DNA binding site to form a stable covalent nitrogen-carbon bond, resulting in permanent DNA modification. This modification process will make DNA insoluble and lost with cell debris during the later genomic DNA extraction process. The unbound PMA remaining in the solution reacts with water molecules under strong light irradiation to decompose into hydroxylamine compounds without cross-linking activity, so that it can no longer covalently bind to DNA. Based on this feature of PMA, PMA was combined with qPCR technology to form a new detection method, PMA-qPCR, for the screening of live bacteria. At present, the method has been verified in a variety of bacterial strains, yeast, fungi, viruses and parasites. The treatment of complex samples, such as manure or soil, may require optimization of sample dilution, dye concentration, and light treatment time. The treatment of diluted samples, such as water testing, may require filtration or concentration prior to dye treatment. Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. the components of the kit contain fluorescent dyes. Avoid light during use and storage. 3. for your safety and health, please wear experimental clothes and disposable gloves.Product parameters:Spectral characteristics :PMA: Ex = 464 nm; Ex/Em = 510/610 nm (following photolysis and reaction with DNA/RNA)Component： PMA：Ex = 464 nm; Ex/Em = 510/610 nm (following photolysis and reaction with DNA/RNA) Instruction： Precautions before use： 1.This live bacteria detection kit distinguishes dead bacteria and live bacteria according to cell membrane permeability. Many methods of killing bacteria cause damage to the cell membrane and are therefore compatible with this kit. But some methods, such as ultraviolet irradiation, may not immediately cause cell membrane rupture. Therefore, before selecting this kit, it is necessary to carry out literature search and pre-experiment to determine whether the kit is suitable for the bacterial type and killing method you choose. 2.After PMA treatment, the bacteria need to be photolyzed to covalently bind the dye to dead cell DNA. Photolysis operations can use blue or white light sources. Generally speaking, the brighter the lamp, the higher the efficiency of the photolysis step. Non-LED lamps ( such as halogen lamps ) may heat your sample and have a negative impact on the analysis. Ice is required to cool the sample during irradiation. 3.Sample can be cryopreservation after photolysis. Frozen samples before PMA treatment photolysis may damage the cell membrane and produce false negative results. If the sample needs to be frozen before detection, it is recommended to perform a pre-experiment first. 4.Part of the mechanism of PMA is to remove PMA covalently modified DNA from the sample by precipitation ; therefore, when extracting genomic DNA, it is necessary to use the same volume of genomic DNA eluent for volume normalization. The positive control can use the genomic DNA of living cells. 5.In order to verify the effectiveness of PMA in the test sample, the Ct ( dCt ) changes between- / + PMA can be compared. Experimental materials ( self-provided )：①Light source ( for the photolysis step after PMA modification of DNA ) ; ② Bacterial genomic DNA extraction kit ; ③ effective qPCR primers corresponding to the sample type Experimental procedure： 1.Suck 10 µL of E.coli bacterial solution in liquid LB medium, and culture E.coli in the bacterial incubator overnight or longer to the logarithmic growth phase ( OD600 ≈ 1.0 ) ; Note : The culture time is adjusted according to the experiment. 2.Two portions of live E.coli, 400 µL each, were placed in a clean centrifuge tube ; 3. ( Recommended ) Preparation of dead E.coli. If the dead E.coli is needed as a control, the dead E.coli can be obtained by heating the living E.coli in a water bath at 95 °C for 5 min, or at 58 °C for 3 h. the subsequent operation of the dead E. coli is the same as that of the living E. coli ; 4.Two copies of live E.coli, one without PMA treatment, and one with 25 µM PMA treatment ( the optimal PMA concentration for treating different types or different sources of bacteria needs to be consulted in the relevant literature ) ; 5.The PMA-treated samples were placed on a shaker at room temperature and incubated in the dark for 10 min to fully mix the dye with the sample ; 6.Exposure of the sample, you can use blue or white light source, irradiation time to explore their own. For example, a 60 W blue light can be used for 15 min. Note : 1 If a halogen lamp is used, we recommend that the PMA-treated sample tube be placed on an ice block 20 cm away from the light source. Ice should be placed in a transparent tray. Adjust the light source to point directly to the sample, photolysis for 5-15 min ; if the bacteria obtained from the environment are directly used for experiments, due to the complexity or turbidity of the environmental samples, the photolysis time needs to be prolonged appropriately. 7.Treated and untreated live E.coli 5000 × g, centrifuged for 10 min, remove the supernatant ; 8.Select the appropriate genomic DNA extraction kit according to the sample type, and use the same elution volume for each group of samples when elution DNA. Note : DNA extraction steps refer to the instructions of the kit used. Part of the mechanism of action of PMA is to remove PMA-bound DNA from the sample by precipitation ; therefore, when extracting genomic DNA, each group should use the same volume of genomic DNA eluent for volume normalization ( the amount of genomic DNA extracted from dead bacteria and live bacteria is inconsistent, so the concentration of the two is significantly different ). 9.Preparation of reaction mixture according to the following system : Note : 1 For the DNA extracted by commercial DNA extraction kit, the qPCR template was optimized with 2 µL as the initial volume ; 2 The template volume should not exceed 10 % of the final reaction volume ; 3 Template concentration : gDNA as template, usually 1-10 ng ; the final concentration of PCR primers is usually 0.4µM, which can get better results. When the reaction performance is poor, the primer concentration can be adjusted in the range of 0.2-1µM. 10.Slightly vortex the reaction mixture, transfer the fixed volume to the PCR tube. 11. Test procedure Note : 1 The extension time is adjusted according to the instrument ; the Taq enzyme in mix can be activated within 2 min, but the genomic DNA may require longer denaturation time, which can be increased at this time, and the specific denaturation time can be adjusted according to the sample type.12. ( Optional ) Data analysis Using live bacteria and dead bacteria as controls, the number of live cells in the sample was analyzed and calculated. It is recommended to verify the suitability of primers and PCR procedures before starting PMA qPCR detection of live bacteria. Calculation of dead and living bacteria control dCt ( 1 ) After the end of qPCR, the Ct value of each sample was calculated by instrument software ; ( 2 ) By calculating the dCt of each control bacteria, it was judged whether PMA successfully inhibited the amplification of dead bacterial DNA. The calculation is as follows : dCt live = Ct ( live, PMA treated ) -Ct ( live, PMA untreated ) dCt die = Ct ( die, PMA treated ) -Ct ( die, PMA untreated ) ( 3 ) The dCt expectation of living bacteria is close to 0 ± 1, which indicates that PMA does not affect the amplification of living cell DNA ;( 4 ) The expected value of dCt of dead bacteria is greater than 4 ( dCt is 4 means that it is reduced by about 16 times, that is, 94 % of dead bacterial DNA is removed ; a dCt of 8 indicated a decrease of about 250 times, that is, 99.6 % of the dead bacterial DNA was removed ).( 5 ) The dCt of dead bacteria depends on many factors, including : strain / cell type ; the way bacteria are killed ; the concentration of PMA used ; amplified sequence length. 13. Calculation of the proportion of viable ( optional ) bacteria If the control results of dead and live bacteria are normal, the proportion of live bacteria in the sample can be calculated.( 1 ) Calculate the dCt value of the sample : dCt sample = Ct ( sample, PMA treated ) -Ct ( sample, PMA untreated ) ( 2 ) Conversion of dCt value to live bacteria ratio : PMA inhibition multiple = 2 ( sample dCt ) Viable bacteria % = 100 / PMA inhibition multiple 14. ( Optional ) Calculate the absolute number of live bacteria If you want to calculate the absolute number of viable bacteria in the sample, you need to use a known number of target bacteria genomic DNA to make a standard curve. It is recommended that the diluted concentrations of several groups of genomes are within the range of the qPCR analysis system.( 1 ) qPCR was performed with the appropriate genome, and the Ct value was used as the ordinate, and the number of cells was used as the abscissa. The R2 value is calculated to determine the linearity, and the slope and y-axis intercept are displayed. ( 2 ) Calculate the copy number of the experimental samples : Ct = slope * cell number + y axis intercept ( y = mx + b ) Bacterial count sample = ( Ct-y axis intercept ) / slope Note : The live bacterial DNA was not lost during the purification process. Examples : Scope of application：Live bacteria detection... Read More | The content of this cell is too long for an XLSX file (more than 32767 characters). Please use the CSV format for this export | Product contentY666144Component50 TStorageY666144ABuffer P115 mLRTY666144BBuffer P215 mLRTY666144CBuffer N320 mLRTY666144DBuffer PS15 mLRTY666144EBuffer PB10 mLRTY666144FBuffer PW (concentrate)10 mLRTY666144GBuffer EB10 mLRTY666144HGlass Beads2 gRTY666144IRNase A (10mg/mL)150 µLRTY666144JSpin Product contentY666144Component50 TStorageY666144ABuffer P115 mLRTY666144BBuffer P215 mLRTY666144CBuffer N320 mLRTY666144DBuffer PS15 mLRTY666144EBuffer PB10 mLRTY666144FBuffer PW (concentrate)10 mLRTY666144GBuffer EB10 mLRTY666144HGlass Beads2 gRTY666144IRNase A (10mg/mL)150 µLRTY666144JSpin Columns DM with Collection Tubes50 setsRTProductsThis kit is improved on the basis of common alkaline lysis method, the glass beads can effectively break the yeast cell wall, the new silica matrix membrane and buffer system can efficiently and specifically bind the plasmid DNA, and at the same time can maximize the removal of proteins and other impurities, the whole process is convenient and fast, no need to use toxic and harmful reagents, and can be processed at the same time for multiple samples. In addition to yeast cells, it can also be used in E. coli. Plasmid DNA extracted with this kit can be used in various molecular biology experiments, such as ligation, transformation, sequencing and library screening.Self-contained reagents: β-mercaptoethanol, anhydrous ethanol.Pre-experiment Preparation and Important Notes1. All components can be stably stored in dry, room temperature (15-30℃) environment for 1 year, the adsorption column can be stored at 2-8℃ for a longer period of time, and Buffer P1 with RNase A can be stably stored at 2-8℃ for 6 months.2. Before the first use, add all the RNase A solution to Buffer P1, mix well, and store at 2-8℃.3. Anhydrous ethanol should be added to Buffer PW before first use according to the instructions on the reagent bottle label.4. Before use, please check whether Buffer P2 and Buffer N3 are crystallized or precipitated. If there is any crystallization or precipitation phenomenon, it can be clarified by taking a water bath at 37℃ for a few minutes to restore the clarity.5. Be careful not to touch Buffer P2 and Buffer N3 directly, and tighten the lid immediately after use.6. The amount of plasmid extracted is related to the yeast strain, plasmid copy number, culture conditions, etc. Usually, yeast plasmid copy number is very low, which is difficult to be detected by electrophoresis or spectrophotometer method.Procedure1. Take 1-5 ml of yeast culture (maximum 5×107 yeast cells, generally for Saccharomyces cerevisiae OD = 1.0, equivalent to 1-2×107 cells/ml) and add it to a centrifuge tube (self-provided), centrifuge for 30 seconds at 12,000 rpm (~13,400×g), collect the bacterial precipitate, and aspirate as much as possible to discard the supernatant.2. Add 250µl Buffer P1 to the bacterium (please check if RNase A has been added first) and resuspend the precipitate.3. Add 40mg of Glass Beads to the above mixture and vortex and shake for 10 minutes.4. Add 250 µl of Buffer P2 to the centrifuge tube, mix gently by turning up and down 6-8 times, and let stand at room temperature for 5-10 minutes, at which time the bacterial solution should become clear and viscous.Note: Mix gently, do not shake violently, so as not to interrupt the genomic DNA, resulting in genomic DNA fragments mixed in the extracted plasmid. If the solution does not become clear, it suggests that the amount of bacteria may be too large and the lysis is not complete, and the amount of bacteria should be reduced.5. Add 350 µl of Buffer N3 to the centrifuge tube and immediately mix gently up and down 6-8 times, at which point a white flocculent precipitate appears, and centrifuge at 12,000 rpm for 20 minutes.Note: Buffer N3 should be mixed immediately after addition to avoid localized precipitation.6. Column Equilibration: Add 200 µl of Buffer PS to the Spin Columns DM in the collection tube, centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid from the collection tube, and place the column back into the collection tube.7. Add the supernatant from step 5 to the adsorbent column that has been loaded into the collection tube, taking care not to aspirate the precipitate.Note: The maximum volume of the adsorption column is 750 µl, and the solution is passed through the column in 2 times.8. Centrifuge at 12,000 rpm for 1 minute, pour off the waste liquid in the collection tube and place the adsorption column back into the collection tube.9. Add 150 µl Buffer PB to the adsorbent column, 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.10. Add 750 µl Buffer PW to the adsorption column (please check that anhydrous ethanol has been added first), centrifuge at 12,000 rpm for 1 minute, and pour off the waste liquid in the collection tube.11. Place the column back into the recovery collection tube and centrifuge at 12,000 rpm for 2 minutes, pouring off the waste liquid. Leave the column at room temperature for several minutes to dry thoroughly.Note: The purpose of this step is to remove residual ethanol from the adsorption column; ethanol residue can interfere with subsequent enzymatic reactions (digestion, PCR, etc.).12. Place the adsorbent column in a new centrifuge tube, add 50-100 µl of Buffer EB to the center of the adsorbent membrane dropwise, let it stand at room temperature for a few minutes, centrifuge at 13,000 rpm for 1 minute, and collect the plasmid solution into the centrifuge tube. Store the plasmid at -20°C.Attention:1) To increase the recovery efficiency of the plasmid, the resulting solution can be reintroduced into the adsorbent column, left at room temperature for a few minutes, centrifuged at 13,000 rpm for 1 minute, and the plasmid solution collected into a centrifuge tube.2) When the plasmid copy number is low or >10 kb, Buffer EB is preheated at 65-70°C in a water bath, which can increase the extraction efficiency.3) Usually yeast plasmids have very low copy number and are difficult to detect by electrophoresis or spectrophotometry. If the extracted plasmid is to be used in the next step of the experiment, it is usually recommended to use 1-5µl of the plasmid as PCR template, and 5-10µl of the plasmid for transformation of E. coli.4) Commercial high transformation efficiency receptor cells should be used for transformation of E. coli... Read More |