CD55 / DAF Protein (His Tag)

Complement Decay-Accelerating Factor ( CD55 / DAF ) Protein

CD55 / DAF Protein Product Information

• Synonym: RP11-357P18.1 , CR , CROM , DAF , TC
• Protein Construction: A DNA sequence encoding the human CD55 precursor ( NP_000565.1 ) ( Met 1 - Ser 353 ) was expressed, with a C-terminal polyhistidine tag
• Source: Human
• Expression Host: Human Cells

CD55 / DAF Protein QC Testing

• Purity: > 95 % as determined by SDS-PAGE
• Bio-activity: Measured by its binding ability in a functional ELISA
  Immobilized human CD55 at 2 μg/ml ( 100 μl/well ) can bind human CD97 with a linear ranger of 1.28 - 32 ng/ml
• Endotoxin: < 1.0 EU per μg of the protein as determined by the LAL method.
• Stability: Samples are stable for up to twelve months from date of receipt at -70℃
• Predicted N terminal: Asp 35
• Molecular Mass: The secreted recombinant human CD55 consists of 330 amino acids and has a predicted molecular mass of 36.5 kDa. In SDS-PAGE under reducing conditions, the apparent molecular mass of rhCD55 is approximately 55-60 kDa due to glycosylation
• Formulation: Lyophilized from sterile PBS , pH 7.4
  1. Normally 5 % - 8 % trehalose and mannitol are added as protectants before lyophilization. Specific concentrations are included in the hardcopy of COA.
  2. Please contact us for any concerns or special requirements.
• SDS-PAGE: CD55 protein

CD55 / DAF Protein Usage Guide

• Storage: Store it under sterile conditions at -70℃. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
• Reconstitution: A hardcopy of COA with reconstitution instruction is sent along with the products. Please refer to it for detailed information.

CD55 / DAF Protein Description

CD55, also well known as decay-accelerating factor (DAF), is a member of the RCA (regulators of complement activation) family characterized by four to 30 SCRs (short consensus repeats) in their plasma-exposed regions. This 70-75 kDa glycoprotein CD55 containing four SCR modules is involved in the regulation of the complement cascade. It interferes with the functions of C3 and C5 convertases in both the classical and alternative pathways by preventing the assembly of the C3bBb complex or accelerating the disassembly of preformed convertase, and thus disrupts the cascade and protects the host cells from damage. Antigens present on the CD55/DAF constitute determinant for the Cromer blood group system. CD55/DAF has been identified as a ligand for an activation-associated, seven-transmembrane lymphocyte receptor, CD97, which is a receptor mediating attachment and infection of several viruses and bacteria. In addition, it has been shown that CD55/DAF regulates the interplay between complement and T cell immunity in vivo, and thus may be implicated in immune and tumor biology. There are two variants of CD55 encoded by alternatively spliced transcripts, the predominant variant is a GPI-anchored membrane form ubiquitously expressed on cells exposed to plasma complement proteins, whereas a soluble form present at much lower level.

References

1. Bergelson, JM. et al., 1994, Proc. Natl. Acad. Sci. USA. 91: 6245-8.
2. Terstappen, LW. et al., 1992, J. Leuro. Biol. 52: 652-60.
3. Liu, J. et al., 2005, J. Exp. Med. 201: 567-77.
4. Madjd, Z. et al., 2004, Clin. Cancer. Res. 10: 2797-803.
5. Mikesch, JH. et al., 2007, Cell. Oncol. 28: 223-32.