Type

Recombinant

Description

LIF is a pleiotrophic factor produced by multiple cell types, including T cells, myelomonocytic lineages, fibroblasts, liver, heart and melanoma. LIF promotes long-term maintenance of embryonic stem cells by suppressing spontaneous differentiation. Other activities include the stimulation of acute phase protein synthesis by hepatocytes, stimulation of differentiation of cholinergic nerves, and suppression of adipogenesis by inhibiting the lipoprotein lipase in adipocytes. While human LIF is active on mouse cells and is widely used in the maintenance of murine ESC to prevent spontaneous differentiation, mouse LIF is not active on human cells due to its inability to bind to the human LIF receptor. Recombinant Human LIF is a 19.6 kDa protein containing 180 amino acids residues, including three disulfide bonds.

Amino Acid Sequence

SPLPITPVNATCAIRHPCHNNLMNQIRSQLAQLNGSANALFILYYTAQGEPFPNNLDKLCGPNVTDFPPFHANGTEKAKLVELYRIVVYLGTSLGNITRDQKILNPSALSLHSKLNATADILRGLLSNVLCRLCSKYHVGHVDVTYGPDTSGKDVFQKKKLGCQLLGKYKQIIAVLAQAF

Source

E. coli

Purity

98%

Biological Activity

Determined by its ability to stimulate the proliferation of human TF-1 cells. The expected ED ₅₀ is ≤ 0.1 ng/ml, corresponding to a specific activity of ≥ 1×10 ⁷ units/mg.

Endotoxin

Endotoxin level is <0.1 ng/μg of protein (<1EU/μg).

Reconstitution

Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1–1.0 mg/ml. Do not vortex. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at –20°C to –80°C.

Storage/Expiration

 –20°C