LIF, bovine

LIF (leukemia inhibitory factor, myeloid leukemia inhibitory factor) a pleiotropic lymphoid factor was initially described as a factor that inhibits the proliferation of myeloid leukemia cells and induces their differentiation into macrophages. Other activities of LIF include inhibition of adipogenesis, cholinergic neuron differentiation and bone metabolism. LIF is often added to stem cell culture medium to reduce spontaneous differentiation. Bovine LIF shares about 88% homology with human LIF and about 75% homology with murine LIF.

Recombinant MESOkine® LIF, bovine is produced in the endosperm tissue of barley seed (Hordeum vulgare).

2xPBS pH 7.2, sterile filtered through 0.45 μm filter.

MESOkine® recombinant bovine LIF is purified from barley seeds resulting in an extract containing purified recombinant bovine LIF protein along with co-purified barley seed proteins. The amount of the recombinant bovine LIF protein is typically in the range of 0.1-5% of total purified protein content. The exact content of the growth factor is stated on the vials. The co-purified barley seed proteins may serve as stabilizing proteins that can prolong the lifetime of the recombinant protein during proper storage and may enhance the bioactivity of growth factors in standardized bioassays.

It is recommended to reconstitute the lyophilized protein in sterile buffered saline or a solution of your choice, preferably to a concentration of no more than 10-100 μg/ml. If needed the reconstituted material may be centrifuged at 3500G for 5 min or filtrated using 0.45 micron filter. 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.

Each batch of MESOkine® growth factor is tested for bioactivity and verified to have comparable activity to a corresponding commercial source of highly purified (>95%) growth factor. The bioactivity of MESOkine® recombinant bovine LIF was determined by its ability to induce proliferation of TF-1 cells in a dose dependent manner. The ED50 value for this effect is typically below 0.3 ng/ml corresponding to specific activity of >3.3 x 10e6 U/mg. Optimal concentration should be determined for specific applications and cell lines..

MESOkine® recombinant bovine LIF contains 180 amino acids and a 6 a.a. histidine tag for a total length of 186 a.a. and has a predicted molecular mass of 20.6 kDa. As a result of glycosylation, the recombinant protein migrates with an apparent molecular mass of 22-30 kDa in SDS-PAGE.