| Description | Leptin (aka OB protein, or Obesity factor protein) is a 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.:Leptin (humanLeptin (aka OB protein, or Obesity factor protein) is a 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.:Leptin (human), (recombinant) is produced in E.Coli as a single, non-glycosylated, polypeptide chain containing 146 amino acids and having a molecular mass of approximately 16 kDa. The Leptin protein is purified by proprietary chromatographic techniques.:Biological Activity is evidenced by inducing proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor.Product descriptionEncoded by the ob (obese) gene, Leptin is an adipose-derived cytokine that suppresses appetite and increases thermogenesis. Leptin exerts its anorectic effect via signaling through a hypothalamic receptor termed OB-R. Leptin has been shown to reduce body weight, food consumption, and plasma glucose levels in various in vivo models. Recombinant Human Leptin is a 16.0 kDa protein containing 147 amino acid residues.SourceE.coliSynonymsObesity protein (OB)AA SequenceMVPIQKVQDD TKTLIKTIVT RINDISHTQS VSSKQKVTGL DFIPGLHPIL TLSKMDQTLA VYQQILTSMP SRNVIQISND LENLRDLLHV LAFSKSCHLP WASGLETLDS LGGVLEASGY STEVVALSRL QGSLQDMLWQ LDLSPGCPurity:≥ 97% by SDS-PAGE gelBiological ActivityFully biologically active when compared to standard. The ED50 as determined by a chemotaxis bioassay using human Leptin R transfected BaF3 murine proB cells is less than 2 ng/ml, corresponding to a specific activity of > 5.0 × 105 IU/mgAccession NumberP41159Gene ID3952FormulationLyophilized from a 0.2 µm filtered concentrated solution in 50 mm PB, pH 3.5, with 0.02 % Tween-20.ReconstitutionWe recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1 % BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20 °C. Further dilutions should be made in appropriate buffered solutions... Read More | Taq MasterMix is a premixed system composed of Taq DNA Polymerase, Mg2+, dNTPs, as well as PCR stabilizers and enhancers, with a concentration of 2 ×. The pre prepared PCR mixture makes the operation simpler and faster, and can minimize human error and contamination to the greatest extent Taq MasterMix is a premixed system composed of Taq DNA Polymerase, Mg2+, dNTPs, as well as PCR stabilizers and enhancers, with a concentration of 2 ×. The pre prepared PCR mixture makes the operation simpler and faster, and can minimize human error and contamination to the greatest extent possible. The original MasterMix formula results in high yield, strong repeatability, and good stability of amplified products. This product has been added with a dye (blue), and can be directly subjected to electrophoresis detection after the reaction is completed. The amplified PCR product has an "A" base attached to its 3 'end, making it suitable for direct use in T/A cloning. Mainly suitable for PCR amplification of DNA, DNA sequencing and other experiments. T665590Component5 mL25 mLStorageT665590A2×Taq MasterMix (Dye)5×1 mL5×5 mL-20℃. Avoid freeze/thaw cycle.T665590BddH₂O5×1 mL5×5 mL-20℃. Avoid freeze/thaw cycle.2×Taq MasterMix contains Taq DNA Polymerase, 3 mM Mg Cl₂ and 400 µM each dNTP. Quality control:After testing, there was no exogenous nuclease activity; PCR method for detecting residual DNA without host; Can effectively amplify single copy genes from multiple genomes.Usage:The following is an example of a PCR reaction system and reaction conditions for amplifying a 1 kb fragment using human genomic DNA as a template. In practical operation, corresponding improvements and optimizations should be made based on the template, primer structure, and target fragment size.1. PCR reaction system Reagent 50 µlReaction system Final concentration 2×Taq MasterMix（Dye） 25 µL 1× Forward Primer，10 µM 2 µL 0.4 µM Reverse Primer，10 µM 2 µl 0.4 µM Template DNA <0.5 µg <0.5 µg/50 µL ddH2O up to 50 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.2. PCR reaction conditions Step Temperature Time / Pre denaturation 94℃ 2 min / Denaturation 94℃ 30 s 25-35 cycles Anneal 55-65℃ 30 s 25-35 cycles Extend 72℃ 30 s 25-35 cycles Finally extended 72℃ 2 min / Attention:1) In general experiments, if the annealing temperature is 5 ° C lower than the melting temperature Tm of the amplification primer, and 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 should be set according to the size of the amplified fragment. The amplification efficiency of Taq DNA Polymerase in this product is 2 kb/min.3) The number of cycles can be set based on the downstream application of the amplification product. If the number of cycles is too small, the amplification amount is insufficient; If there are too many cycles, the probability of mismatches will increase, and non-specific backgrounds will be severe. So, while ensuring product yield, the number of cycles should be minimized as much as possible... Read More | Product introduction：Aladdin ® SE is a kind of fluorescent dye with amino reactive activity. The SE group of these dyes can react with the amino group to produce a stable amide bond. Compared with other similar dyes on the market, aladdin ® is a new generation of fluorescent dyes Product introduction：Aladdin ® SE is a kind of fluorescent dye with amino reactive activity. The SE group of these dyes can react with the amino group to produce a stable amide bond. Compared with other similar dyes on the market, aladdin ® is a new generation of fluorescent dyes with stronger stability, better water solubility and better fluorescence intensity. Product parameters： Absmax/Em(nm)：648/664；Absmax/Em(nm)：0.03；Extinction coefficient(ε)：240000；Optimal DOL(IgG)：3-6； Usage:1. Experimental materials(1) IgG: IgG must not contain amine chemicals that can react with dyes, such as amino acids, Tris, BSA, gelatin, etc. If IgG contains such chemicals, PBS buffer with pH~7.4 should be used for pre dialysis treatment. The presence of azide compounds does not affect the labeling reaction.(2) Anhydrous DMSO(3) NaHCO3(4) Sephadex gel G-25 dialysis column(5) PBS buffer (pH~7.4)(6) NaN3(7) BSA2. Marking methods and steps(1) Prepare to label antibodiesDilute the antibody with 0.1 M NaHCO3 solution (pH~8.3) to a final concentration of 2.5 mg/mL. If the product is pre diluted with phosphate buffer, such as PBS buffer (without amino compounds), approximately 1/10 volume of 1M NaHCO3 mother liquor can be directly added to the buffer to achieve a final NaHCO3 concentration of 0.1 M.Note: When the protein concentration is 2.5 mg/mL, the labeling efficiency is approximately 35%. Protein concentrations below 2.5 mg/mL can also be used for labeling, but the labeling efficiency will decrease. When the protein concentration is higher than 5 mg/mL, the labeling efficiency may be higher. Due to differences in buffer and protein purity, more precise labeling efficiency is determined by practical operating conditions. If the protein concentration is too low, it can be concentrated by ultrafiltration.(2) Prepare dye storage solutionPreheat one tube at room temperature µ YF of Mole ® SE, add 0.1 mL of anhydrous DMSO to the tube, thoroughly vortex dissolve the dye, and prepare a dye storage solution with a concentration of 10 mM. If a trace amount of protein is used for labeling reactions, the dye needs to be diluted to a lower concentration.Note: a The remaining dye storage solution should be stored at a low temperature of -20 ℃ for future use. If anhydrous DMSO is used to prepare dye storage solution, the dye can be stored for at least one month.b. Dyes can also be prepared with deionized water, but due to the slow hydrolysis of dyes in water, it is best to prepare water based storage solutions for immediate use.(3) Mark reaction stepsa. Stir or vortex the protein solution, gradually adding 15-25 drops µ L dye storage solution (10 mM), with a molar ratio of dye/protein in the range of 9:1 to 15:1. YF ® Please refer to the table above for the range of DOL (number of dyes bound to each protein molecule) for SE labeled IgG antibodies.b. Stir the reaction at room temperature for 1 hour, and for trace labeling, shake and incubate on a shaker for 1 hour.Note: At the same time of the binding reaction, proceed to step 2 (4) to balance the dextran gel G-25 dialysis column.(4) Isolation of marker proteins from reaction solutiona. PBS buffer (pH~7.4) was used to balance the dextran gel G-25 dialysis column (10 mm × 300 mm).b. Add the reaction solution from step 3 (b) to the column and elute with 1 x PBS buffer.The first washed out chromophore is a dye protein complex.Note: a For small-scale labeling reactions, in order to avoid excessive dilution of the product, ultrafiltration devices can be used to remove free dyes from the complex.b. After the binding reaction is completed, if the dye protein complex is not separated in time, 50 can be added µ Terminate the reaction with L 1M lysine. In most cases, this operation is not necessary because the remaining unreacted dyes have been fully hydrolyzed at the end of the reaction.3. Determine DOL(1) The determination of protein concentration and antibody concentration can be calculated using the following formula:C (mg/mL)={[A280- (Amax x x Cf)]/1.4} x dilution factor;a. C refers to the concentration of antibodies collected in the experiment;b. Dilution factor refers to the dilution factor used in photometric measurements;c. A280 and Amax refer to the absorbance at 280 nm and the absorbance at the absorption wavelength, respectively;d. Cf is the correction factor, YF ® Please refer to the table above for the Cf value of SE dyes;Note: The protein solution eluted through the column may have a high concentration when used directly for absorbance detection, so it needs to be diluted to approximately 0.1 mg/mL. The dilution factor (i.e. dilution factor) needs to be determined from the initial number of antibodies (e.g. 5 mg) and the overall elution of protein solutionEstimate based on the product.(2) Estimation of DOLDOL is calculated using the following equation:DOL=(Amax x x Mwt x Dilution Factor)/（ ε X C)a. Amax, dilution factor, C value has been clearly defined in 3 (1);b. Mwt refers to the molecular weight of IgG (150000);C. c ε It's YF ® The molar absorption coefficient of SE, refer to the table on the first page;d. Mark YF ® The optimal DOL value for SE IgG antibodies can be found in the table on the first page. Although DOL values may fluctuate, good experimental results can also be achieved.Matters needing attention：1. if the labeled protein needs long-term storage, it is recommended to add 5-10 mg/ml BSA and 0.01-0.03% NaN3 to prevent protein denaturation and microbial breeding. Store at 4 ℃ away from light. If glycerol with a final concentration of 50% is added, it can be stored at -20 ℃. It can be stably stored for more than one year. 2. keep away from light during operation. The mixing speed should be appropriate to avoid bubbles. 3. when installing the chromatographic column, try to make the column body uniform, the column surface flat, and free of bubbles and cracks. 4. pay attention to adding the sample when the column top buffer is tangent to the gel plane. When eluting, add the eluent when the sample is tangent to the gel plane. 5. other factors affecting the labeling efficiency also include temperature, reaction time, pH, the amount of fluorescent dye and protein, etc., which should be controlled. 6. for your safety and health, please wear laboratory clothes and disposable gloves.Scope of application：Protein nucleic acid labeling dye... Read More | Inquire | Purity: >95%, by SDS-PAGE visualized with Coomassie® Blue Staining. Description： CD4, also known as L3T4, T4, and W3/25, is an approximately 55 kDa type I transmembrane glycoprotein that is expressed predominantly on thymocytes and a subset of mature T lymphocytes. It is a standard Purity: >95%, by SDS-PAGE visualized with Coomassie® Blue Staining. Description： CD4, also known as L3T4, T4, and W3/25, is an approximately 55 kDa type I transmembrane glycoprotein that is expressed predominantly on thymocytes and a subset of mature T lymphocytes. It is a standard phenotype marker for the identification of T cell populations. Mature human CD4 consists of a 371 amino acid (aa) extracellular region containing four immunoglobulin-like domains, a 22 aa transmembrane segment, and a 40 aa cytoplasmic domain. Within the ECD, human CD4 shares approximately 52% aa sequence identity with mouse and rat CD4. CD4 is expressed along with CD8 on double positive T cells during their development in the thymus. Either CD4 or CD8 expression is then lost, giving rise to single positive (SP) CD4+ or CD8+ mature T cells. CD4+ SP cells, also known as T helper cells, further differentiate into multiple subsets of CD4+ cells including Th1, Th2, Th17, Tfh, and Treg cells which regulate humoral and cellular immunity. CD4 is reexpressed on circulating CD8+ T cells upon activation and contributes to their cytotoxic effector activity. In human, CD4 is additionally expressed on macrophages, neutrophils, monocytes, NK cells, and neurons and glial cells in the brain. Similar CD4 distribution between species cannot be assumed as demonstrated by its presence on macrophages in human and rat but not in mouse. CD4 binds directly to MHC class II molecules on antigen presenting cells. This interaction contributes to the formation of the immunological synapse which is focused around the TCR-MHC class II-antigenic peptide interaction. Palmitoylation of two cysteine residues in the cytoplasmic tail of CD4 promotes the localization of CD4 in lipid rafts and its ability to augment TCR signaling via activation of the tyrosine kinase Lck. CD4 also functions as a chemotactic receptor for IL-16 and, in human, as a co-receptor for the gp120 surface glycoprotein of HIV-1... Read More |