| Synonyms | SDF-1, CXCL12, Pre-B cell growth-stimulating factor, PBSF, hIRH, chemokine （C-X-C motif） ligand 12, SDF1, SDF1B, TPAR1, SCYB12, SDF-1b, TLSF-b. |
| Introduction | 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）. It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/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 and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend 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. |
| Description | Stromal Cell-Derived Factor-1 beta Human Recombinant produced in E.Coli is a non-glycosylated, Polypeptide chain containing 72 amino acids and having a molecular mass of 8508 Dalton.
The SDF-1b is purified by proprietary chromatographic techniques. |
| Source | Escherichia Coli. |
| Physical Appearance | Sterile Filtered White lyophilized （freeze-dried） powder. |
| Formulation | The CXCL12 protein was lyophilized from a concentrated （1mg/ml） sterile solution containing no additives. |
| Solubility | It is recommended to reconstitute the lyophilized Stromal Cell-Derived Factor-1b in sterile 18MΩ-cm H2O not less than 100μg/ml, which can then be further diluted to other aqueous solutions. |
| Stability | Lyophilized SDF-1b although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution CXCL12 should be stored at 4°C between 2-7 days and for future use below -18°C. For long term storage it is recommended to add a carrier protein （0.1% HSA or BSA）.
Please prevent freeze-thaw cycles. |
| Purity | Greater than 98.0% as determined by（a） Analysis by RP-HPLC.
（b） Analysis by SDS-PAGE. |
| Amino acid sequence | The sequence of the first five N-terminal amino acids was determined and was found to be Lys-Pro-Val-Ser-Leu. |
| Biological Activity | The specific activity as determined by its ability to chemoattract human peripheral T cells activated with PHA and IL-2 using a concentation of 20-80 ng/ml. |
| Protein content | Protein quantitation was carried out by two independent methods: 1. UV spectroscopy at 280 nm 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 （InliGenetics）.
2. Analysis by RP-HPLC, using a standard solution of SDF-1? as a Reference Standard. |
| Usage | Prospec's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals. |
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