Cat. No.: BL-Z00384

Source: E. coli

MW: 19,717 Da

Description:
Leukemia Inhibitory Factor (LIF) is a lymphoid factor that promotes long-term maintenance of embryonic stem cells by suppressing spontaneous differentiation. LIF has a number of other activities including cholinergic neuron differentiation, stem cell pluripotency control, bone and fat metabolism, mitogenesis of certain factor-dependent cell lines, and the promotion of megakaryocyte production in vivo. Mature human and murine mature LIFs exhibit 78% sequence identity at the amino acid control.Human LIF is equally active on both human and mouse cells. Murine LIF is approximately 1000 times less active on human cells than hLIF. Recombinant Human LIF produced in E. coli is a single, non-glycosylated, polypeptide chain containing 180 amino acids and having a molecular mass of 19,717 Da.

Purity:
Greater than 95% as determined by the following methods:
(a) RP-HPLC analysis
(b) Anion-exchange FPLC
(c) Reducing and non-reducing SDS-PAGE silver-stained gel
analysis

Endotoxin Level:
Less than 0.1 ng/ug (1 IEU/ug) of LIF

Specific Activity:
The ED50 is determined by the M1 cell differentiation assay is < 0.01 ng/ml, corresponding to a specific activity of > 1×10⁸ units/mg.

Storage:
Lyophilized rHuLIF remains stable at room temperature for three weeks, but it is best stored desiccated below -18°C. Upon reconstitution rHuLIF should be stored at 4°C for up to one week and -18°C for longer periods it is recomme nded that a carrier protein (0.1% HSA or BSA) be added. Please avoid repeated freeze-thaw cycles

Formulation:
LIF is lyophilized after extensive dialysis against PBS.

Reconstitution:
We recommend a quick spin followed by reconstitution in water to a concentration of 0.1-1.0 mg/ml. We also recommend that further dilutions be made into buffer or medium to which protein (e.g., 1% BSA) or Tween 20 has been added. This solution can then be stored at 4°C for one week or at -20°C for longer periods.

Sequence analysis:
The sequence of the first five N-terminal amino acids has been found to be Ser-Pro-Leu-Pro-Ile.