Biolegend, 712856, Recombinant Human CD45 (carrier-free), 100μg

CD45, also known as leukocyte common antigen (LCA) or T200, is a single-chain type I transmembrane glycoprotein and a member of the protein tyrosine phosphatase (PTP) family. It is expressed on the surface of all nucleated hematopoietic cells, excluding erythrocytes and platelets. CD45 plays an essential role in immune regulation by modulating signaling thresholds in lymphocytes. CD45 has multiple isoforms (e.g., CD45RA, CD45RB, CD45RO) that are differentially expressed depending on the cell type, activation state, and developmental stage. These isoforms are frequently used as markers to distinguish naïve, memory, and effector T cell subsets. Functionally, CD45 acts as a tyrosine phosphatase that removes inhibitory phosphate groups from key signaling molecules such as the Src family kinases Lck and Fyn, thereby promoting downstream signaling through the T cell receptor (TCR) and B cell receptor (BCR) pathways. CD45 is required for proper lymphocyte development, activation, and homeostasis. Its expression level and isoform usage can influence TCR signaling strength and the outcome of immune responses. CD45 also forms non-covalent associations with other membrane proteins, including lymphocyte phosphatase-associated phosphoprotein (LPAP), and has been reported to bind to galectin-1, galectin-3, and galectin-9. CD45 is involved in various immune-mediated diseases and hematologic malignancies. Aberrant expression or mutation of CD45 has been linked to immune dysregulation, autoimmune diseases, and lymphoproliferative disorders. Due to its broad expression on leukocytes, CD45 is widely used as a pan-leukocyte marker in flow cytometry and immunohistochemistry. Its selective isoform expression also serves as a useful tool in immunophenotyping, particularly in identifying T cell subsets and monitoring immune reconstitution or disease progression in clinical settings.
100μg
Source: Recombinant human CD45, amino acid Gln26-Lys577 (Accession No. P08575.3) with a C-terminal 6His tag was expressed in CHO cells.
Molecular Mass: The 558 amino acid recombinant protein has a predicted molecular mass of approximately 61.6 kD. The DTT-reduced and non-reduced proteins migrate at approximately 115 - 140 kD by SDS-PAGE. The N-terminal amino acid is Gln.
Purity: > 95%, as determined by Coomassie stained SDS-PAGE.
Formulation: 0.22 µm filtered protein solution is in PBS, pH 7.2
Endotoxin Level: Less than 0.1 EU per µg protein as determined by the LAL method.
Concentration: 25 µg size is bottled at 200 µg/mL. 100 µg size and larger sizes are lot-specific and bottled at the concentration indicated on the vial. To obtain lot-specific concentration and expiration, please enter the lot number in our Certificate of Analysis online tool.
Storage & Handling: Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
Activity: Recombinant human CD45 binds to immobilized recombinant human Galectin-9 (Cat. No. 764806) in a dose-dependent manner. The ED50 for this effect is 40 – 280 ng/mL
Application: Bioassay
Application Notes: BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at [email protected].
Structure: Monomer
Distribution: Hematopoietic cells, not expressed in circulating erythrocytes or platelets
Function: TCR and BCR mediated activation
Interaction: Lymphocytes, dendritic cells, neutrophils, eosinophils, astrocytes, endothelial cells, fibroblasts, thymus stromal cells, epithelial cells, macrophages, neutrophils, monocytes, NK cells, and neurons
Ligand/Receptor: Galectin-1, Galectin-9, CD2, CD3, CD4
Bioactivity: Measured by its ability to bind human Galectin-9
Antigen References: Penninger JM, et al. 2001. Nat. Immunol. 2:389. Clayton KL, et al. 2014. J Immunol. 192:782. Pace KE, et al. 1999. J Immunol. 163:3801. Stillman BN, et al. 2006. J Immunol. 176:778. Hermiston ML, et al. 2003. Annu. Rev. Immunol. 21:107. Huntington, N.D, et al. 2006. Nat. Immunol. 7:190. Freiberg BA, et al. 2002. Clin. Nat. Immunol. 3:911.
Gene ID: 5788
UniProt: View information about CD45 on UniProt.org
Regulatory Status: RUO
Other Names: Protein tyrosine phosphatase, PTPRC, receptor-type tyrosineprotein phosphatase C, B220, CD45, GP180, LCA, L-CA, Leukocytecommon antigen, LY5, T200
Q: Why choose BioLegend recombinant proteins?
A: • Each lot of product is quality-tested for bioactivity as indicated on the data sheet.
     • Greater than 95% Purity or higher, tested on every lot of product.
     • 100% Satisfaction Guarantee for quality performance, stability, and consistency.
     • Ready-to-use liquid format saves time and reduces challenges associated with reconstitution.
     • Bulk and customization available. Contact us.
     • Learn more about our Recombinant Proteins.
Q: How does the activity of your recombinant proteins compare to competitors?
A: We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
Q: What is the specific activity or ED50 of my recombinant protein?
A: The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.
Q: Have your recombinants been tested for stability?
A: Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
Q: Does specific activity of a recombinant protein vary between lots?
A: Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
Q: How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
A: Use formula Specific activity (Units/mg) = 10^6/ ED50 (ng/mL)