Flt3-ligand, rHuman, Animal Free, High Purity/Bioactivity

Flt3-ligand (FMS related tyrosine kinase 3 ligand, flk-2 ligand) is involved in proliferation and differentiation of early hematopoietic cells. Flt3-ligand synergizes with other CSF's and interleukins to induce proliferation of early hematopoietic cells but does not stimulate growth or differentiation alone. Flt3-ligand binds to cells expressing the tyrosine kinase receptor Flt3. Multiple isoforms of Flt3 ligand have been identified but the predominant biologically active isoform is a transmembrane protein which can be proteolytically cleaved to generate a biologically active soluble form. Source: Produced in the endosperm tissue of barley grain (Hordeum vulgare). Formulation: PBS pH 7.2, sterile filtered through 0.2 µm filter. Purity: Greater than 95% by SDS-PAGE gel analysis. Reconstitution: Note: Always centrifuge the vial before opening. It is recommended to reconstitute the lyophilized protein in sterile buffered saline to a concentration of no less than 100 µg/ml. For long term storage of the reconstituted solution it is recommended to add a carrier protein (0.1% HSA or BSA). Stability: The lyophilized protein, though stable at room temperature for few weeks, is best stored at -20°C. Reconstituted protein should be used immediately or stored in working aliquots at -20°C. Avoid repeated freeze-thaw cycles. Biological Activity: The bioactivity of ISOkine(R) recombinant human Flt-3 ligand was assayed by measuring its dose dependent effect on proliferation of AML5 cells. The ED50 value for this ISOkine is < 0.3 ng/ml corresponding to specific activity > 3.3 x 10e6 U/mg. We recommend that the optimal concentration for each specific application be determined by an initial dose response assay. Each batch of this ISOkine(R) growth factor is tested for bioactivity and verified to have comparable activity to a commercial source. Endotoxin Level: Endotoxin level is less than 0.005ng per µg of ISOkine(R) product (0.05EU/µg). MAT Assay: Purified ISOkine(R) product carries no pyrogenic or pro-inflammatory contaminants, as assayed with monocyte activation test using Human 10-plex Cytokine Assay measuring IL-6, TNF-alpha and IL-1beta induction. ** Ref. The Blood Bank, University Hospital of Iceland, Reykjavik, Iceland Molecular Weight: Recombinant human Flt3-ligand contains 156 amino acids and a 16 a.a. Histidine-based tag for a total length of172 a.a. and has a predicted molecular mass of 19.9 kDa. As a result of glycosylation, the recombinant protein migrates as two bands with an apparent molecular mass of 20 and 22 kDa in SDS-PAGE.