Recombinant Human LIF (E. coli)
|Description||LIF is a multifunctional secreted glycoprotein that exists in both soluble and matrix bound forms. It displays biologic activities ranging from the differentiation of myeloid leukemic cells into macrophage lineage to effects on bone metabolism, inflammation, neural development, embryogenesis, and the maintenance of implantation. It is now clear that LIF is related in both structure and mechanism of action to the interleukin IL-6 family of cytokines, which also includes IL-11, ciliary neurotrophic factor, oncostatin M, and cardiotrophin 1. The actions of these cytokines are mediated through specific cell-surface receptors that consist of a unique chain and the shared signal transducing subunit gp130.|
|Aliases||LIF, Differentiation-stimulating factor, D factor, Melanoma-derived LPL inhibitor (MLPLI) |
Recombinant Human Leukemia Inhibitory Factor (LIF)
|Species||Human (H. sapiens)|
|Molecular Weight||20 kDa|
|Endotoxin Level||<1.0 EU/µg of recombinant protein as determined by the LAL method|
|Purity||>95% as determined by SDS-PAGE|
|Formulation||Lyophilized from a 0.2 μm filtered PBS pH 7.0|
|Function||The ED50 was in found to be <0.05 ng as determined by the dose-dependent proliferation of human erythroleukemic cell line.|
|Reconstitution||A quick spin of the vial followed by reconstitution in distilled water to a concentration not less than 0.1 mg/mL. This solution can then be diluted into other buffers.|
|Storage||The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at 2° - 8°C for one month, or at -20°C for six months, with a carrier protein without detectable lo|
|Usage||For research use only. Not for diagnostic or therapeutic use.|
- Growth Factor eFlyer
- Growth Factor and Cytokine Brochure
- Active Kinases Brochure
- Growth Factors and Cytokines Catalogue
- Growth Factors and Cytokines FAQ
- Role of Growth Factors in Cell Differentiation (Poster)
|How are endotoxin levels measured?|
1. For estimating the endotoxin levels; we use the LAL (Limulus Amebocyte Lysate) method: The lysate from horseshoe crab amebocytes clots in the presence of very low endotoxin. This reaction is the basis of the Limulus amebocyte lysate (LAL) assay which was approved by the FDA in 1970. · Endotoxin is generally measured in Endotoxin Units per milliliter (EU/mL). · For recombinant proteins: EU is reported per microgram of protein. · One EU = 0.1-0.2 ng endotoxin/µg of protein. · At abm, we do the LAL chromogenic assays that can detect down to 0.01 EU/ml.
|With regard to the BSA levels in some Growth Factors and Cytokines, can you please provide an explanation as to why they are so high?|
The amount of BSA, as part of the formulation of a protein, can vary considerably depending on how much BSA was deemed optimum/necessary for protein stability in combination with /in-lieu of - other possible additives. The aforementioned formulations are somewhat analogous to the “carrier” versions of many formulations from “R and D systems” that have as high as 50 µg of BSA per µg of the recombinant protein product. If, needed or desired, abm scientists can substitute BSA for other stabilizing additives for most formulations.
|Are your Escherichia coli sourced growth factors: 1) Human derived materials free? 2) Recombinant proteins free?|
Yes, all of abm's growth factors made in Escherichia coli using recombinant technology contain no human derived-products or other recombinant proteins. In the rare cases of BSA presence, this will be mentioned in the product's formulation.
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