Siglec-3/CD33 Protein, Human (HEK293, Fc-Myc)

Siglec-3/CD33 protein is a sialic acid-binding lectin that mediates cell-cell interactions and maintains immune cell quiescence. It prefers α-2,3- and α-2,6-linked glycans with sialic acid. Siglec-3/CD33 Protein, Human (HEK293, Fc-Myc) is the recombinant human-derived Siglec-3/CD33 protein, expressed by HEK293 , with C-Myc, C-Fc labeled tag. The total length of Siglec-3/CD33 Protein, Human (HEK293, Fc-Myc) is 242 a.a., with molecular weight of ~92 kDa.

The Siglec-3/CD33 protein, a sialic-acid-binding immunoglobulin-like lectin, plays a crucial role in mediating cell-cell interactions and maintaining immune cells in a resting state. It exhibits a preference for recognizing and binding alpha-2,3- and more avidly alpha-2,6-linked sialic acid-bearing glycans. Upon engagement with ligands like C1q or sialylated glycoproteins, two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) within CD33's cytoplasmic tail undergo phosphorylation by Src-like kinases such as LCK. These phosphorylated ITIMs serve as docking sites for recruiting and activating protein-tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2, which, in turn, regulate downstream pathways through dephosphorylation of signaling molecules. CD33's repressive effect on monocyte activation involves phosphoinositide 3-kinase/PI3K. Structurally, the protein forms homodimers through disulfide linkages and interacts with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation. It also engages with C1QA via its C-terminus, activating CD33 inhibitory motifs.

Measured by its binding ability in a functional ELISA. Immobilized CD33 at 2 μg/mL can bind Anti-CD33 rabbit monoclonal antibody and the EC₅₀ of human CD33 protein is 0.4375-0.6651 ng/mL.

Human

HEK293

C-Myc;C-Fc

P20138 (D18-H259)

945  [NCBI]

DPNFWLQVQESVTVQEGLCVLVPCTFFHPIPYYDKNSPVHGYWFREGAIISRDSPVATNKLDQEVQEETQGRFRLLGDPSRNNCSLSIVDARRRDNGSYFFRMERGSTKYSYKSPQLSVHVTDLTHRPKILIPGTLEPGHSKNLTCSVSWACEQGTPPIFSWLSAAPTSLGPRTTHSSVLIITPRPQDHGTNLTCQVKFAGAGVTTERTIQLNVTYVPQNPTTGIFPGDGSGKQETRAGVVH

Approximately 92 kDa

Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder.

Lyophilized from a 0.2 μm solution of PBS, 6% Trehalose, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O.

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US;may vary elsewhere.