Stromal Cell Derived Factor 1 beta, Recombinant, Human (SDF1b, CXCL12b, Pre-B Cell Growth-stimulating Factor, PBSF, hIRH, Chemokine (C-X-C Motif) Ligand 12b, TPAR1, SCYB12, TLSF-b)
|Molecular Biology||Storage: -20°CShipping: RT|
Recombinant Human SDF-1b is a non-glycosylated, Polypeptide chain containing 72 amino acids and having a molecular mass of 8508 Dalton.
SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). Stromal cell-derived factors 1-alpha and 1-beta are small cytokines that belong to the intercrine family, members of which activate leukocytes and are often induced by proinflammatory stimuli such as lipopolysaccharide, TNF, or IL1. The intercrines are characterized by the presence of 4 conserved cysteines which form 2 disulfide bonds. They can be classified into 2 subfamilies. In the CC subfamily, which includes beta chemokine, the cysteine residues are adjacent to each other. In the CXC subfamily, which includes alpha chemokine, they are separated by an intervening amino acid. The SDF1 proteins belong to the latter group. SDF-1 is produced in two forms, SDF-1a/CXCL12a and SDF-1b/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid.
CXCL12 is strongly chemotactic for lymphocytes. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow and the formation of large blood vessels. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. In adulthood CXCL12 plays an important role in angiogenesis by recruiting endothelial progenitor cells (EPC) from the bone morrow through a CXCR4 dependent mechanism. It is this function of CXCL12 that makes it a very important factor in carcinogenesis and the neovascularisation linked to tumor progression.  CXCL12 was shown to be expressed in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor. The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.
The sequence of the first five N-terminal amino acids was determined and was found to be Lys-Pro-Val-Ser-Leu.
Dimers and Aggregates:
1% as determined by silver-stained SDS-PAGE gel analysis.
SDF-1b is fully biologically active when compared to standard. The specific activity as determined by its ability to chemoattract human peripheral T cells activated with PHA and IL-2 using a concentation of 20-80ng/ml.
0.1ng/ug (IEU/ug) of Recombinant Human Stromal Cell-Derived Factor-1 beta.
SDF-1b protein quantitation was carried out by two independent methods:
1. UV spectroscopy at 280nm using the absorbency value of 1.06 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).
2. Analysis by RP-HPLC, using a calibrated solution of Recombinant Human Stromal Cell-Derived Factor-1 beta as a Reference Standard.
Reconstitute the lyophilized SDF-1beta in sterile 18MO-cm H2O not less than 100µg/ml, which can then be further diluted to other aqueous solutions.
Storage and Stability:
Lyophilized powder may be stored at 4°C for short-term only. Reconstitute to nominal volume by adding sterile dH2O and store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.
Source: E. coli
Purity: 98% by RP-HPLC, FPLC, or reducing/non-reducing SDS-PAGE Silver Stain. Chromatographically purified.
Form: Supplied as a lyophilized powder. No additives.
Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.