C1QB / C1qB Protein (His Tag)

Complement C1q Subcomponent Subunit B / C1QB Protein

C1QB / C1qB Protein Product Information

• Synonym: C1QB
• Protein Construction: A DNA sequence encoding the human C1QB ( NP_000482.3 ) precursor ( Met 1 - Ala 253 ) was expressed, with a carboxy-terminal polyhistidine tag
• Source: Human
• Expression Host: Baculovirus-Insect cells

C1QB / C1qB Protein QC Testing

• Purity: > 94 % as determined by SDS-PAGE
• 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: Gln 28
• Molecular Mass: The recombinant human C1QB consists of 237 amino acids with the predicted molecular mass of 25 kDa. As a result of glycosylation, rhC1QB migrates as an approximately 30 kDa band in SDS-PAGE under reducing conditions.
• Formulation: Lyophilized from sterile 50mM Tris, 100mM NaCl, 0.5mM TCEP, 10%glycerol , 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: C1QB protein

C1QB / C1qB 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.

C1QB / C1qB Protein Description

C1q circulates in the blood of normal individuals within C1, a calcium-dependent tri-molecular complex composed of equimolar ratios of C1q:C1r:C1s. C1q is synthesized by a number of cell types including hepatocytes, Kupffer cells, macrophages, dendritic cells, microglial cells, fibroblasts, epithelial cells of small intestine, and newborn foreskin epidermal keratinocytes. C1q is the recognition element of C1 that initiates activation of the classical pathway of complement. C1q is a 460,000 kD glycoprotein composed of 18 polypeptide chains: six C1qA chains (223 amino acid residues), six C1qB chains (226 residues), and six C1qC (g) chains (217 residues). The A and B chains are linked by a single disulphide bond to yield six A-B dimer subunits, and pairs of C chains are also linked by a single disulphide bond to yield three C-C dimer subunits. The six C-terminal globular domains of C1q (each containing a C1qA, C1qB, and C1qC chain) associate in a ‘‘bouquet of tulips’’.As a part of the recognition set of the complement C system, the expression of C1qB increases with age in macrophages which are involved in a large number of liver diseases. Additionally, in the neocortex and cerebellum, C1qb is up-regulated with age as is the in the liver.

References

1. Kenneth B. M. Reid, et al., 1978, Biochem J., 173: 863-868
2. Richard D. Sontheimer, et al., 2005, J Invest Dermatol, 125: 14 - 23
3. Shelley X. Cao, et al., 2001, PNAS, vol. 98, no. 19: 10630–10635.