Biolegend, 714356, Biotinylated Recombinant Human CD33 (Siglec-3) (carrier-free), 100μg

Siglec proteins (sialic acid binding Ig-like lectins) are type I membrane proteins with an extracellular region containing a sialic acid binding V-set Ig-like domain at the N-terminus, followed by varying numbers of C2-set Ig domains. In the cytosolic domain, most Siglecs contain a combination of tyrosine motifs, including immunoreceptor tyrosine-based inhibitory motifs (ITIM), along with ITIM-like, Grb2-binding, and Fyn kinase sites. Siglecs are widely expressed on hematopoietic cells, often in a cell-type-specific manner. Their ligands, sialic acids, are negatively charged monosaccharides found on cell-surface glycoproteins and glycolipids. Studies suggest that Siglecs may participate in cell-cell interactions and act as receptors for the entry of viral or bacterial pathogens. In addition, the presence of ITIM indicates that these molecules play a role in the suppression of immunoreceptor signaling. Siglecs can be classified into two subgroups with Siglec 1, 2, and 4, as one group and a Siglec 3/CD33-related subgroup (Siglec 3 and 5 through 14) as the second. Siglec 3, also known as CD33 and GP67, is mainly expressed on myeloid cells and on activated NK and T cells. Human Siglec 3 has two tyrosine residues in its cytoplasmic domain. When phosphorylated, these tyrosines could confer an inhibitory function. CD33 polymorphism has been associated with late-onset Alzheimer's disease.
100μg
Source: Biotinylated Recombinant Human CD33 (Siglec-3), amino acid (Asp18-His259) (Accession # P20138.2), with a C-terminal His tag, and an Avi-tag, was expressed in CHO cells. Human CD33-Avi tag was site-specifically biotinylated by enzyme BirA.
Molecular Mass: The 263 amino acid recombinant protein has a predicted molecular mass of approximately 29.5 kD. The DTT-reduced and non-reduced proteins migrate at approximately 35 - 62 kD by SDS-PAGE. The predicted N-terminal amino acid is Asp.
Purity: > 95%, as determined by Coomassie-stained SDS-PAGE
Formulation: 0.22 µm filtered protein solution is in 20 mM Tris, 300 mM NaCl, 0.5 M L-Arginine, 10% Glycerol, pH 8.0
Endotoxin Level: Less than 0.1 EU per μg of cytokine 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 the 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: Immobilized Biotinylated Recombinant Human CD33 (Siglec-3) supports the adhesion of U937 cells in a dose-dependent manner with an ED50 range of 0.8 – 4.8 µg/mL.
Application: Biossay
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: Homodimer
Distribution: Human Siglec 3 is highly expressed on myeloid cells and activated NK and T cells, but is expressed poorly on B lymphocytes.
Function: Siglec 3 recruits the tyrosine phosphatases SHP-1 and SHP-2 to its ITIMs. When cross-linked with FcgR1, Siglec 3 inhibits phosphorylation of tyrosine residues and the mobilization of calcium, suggesting that it may mediate inhibitory signals.
Interaction: Red blood cells
Ligand/Receptor: α2, 3- and α2, 6-linked disialic acid
Bioactivity: Human CD33 (Siglec-3) supports the adhesion of U937 cells in a dose-dependent manner.
Cell Type: Hematopoietic stem and progenitors
Biology Area: Stem Cells
Molecular Family: Siglec Molecules
Antigen References: McMillan SJ, et al. 2013. Blood. 121:2084-94. Angata T and Varki A. 2000. J. Biol. Chem. 275:22127-35. Yu Z, et al. 2001. Biochem. J. 353:483-92. Paul SP, et. al. 2000. Blood. 96:483-90. Hernandez-Caselles T, et al. 2006. J. Leukoc. Biol. 79:46-58. Jiang T, et al. 2013. Mol. Neurobiol. 49:529-35. Angata T. 2014. Glycobiology. 24:785-93.
Gene ID: 945
UniProt: View information about CD33 on UniProt.org
Regulatory Status: RUO
Other Names: CD33, gp67