Apolipoprotein E Protein, Human, Recombinant (His & Trx Tag), Biotinylated

Apolipoprotein E (ApoE) is a 34.2 kDa glycosylated protein with 299 amino acid residues. There are three isoforms in human (apoE2, apoE3, and apoE4) due to different amino acid residues at positions 112 and 158. ApoE is synthesized predominantly in the liver, but also by cells in the spleen, brain, lung, kidney, ovary, adrenal, and muscle tissues. Hepatic parenchyma cells are the main apoE producing cells in mammalian body, probably accounting for two thirds to three fourths of the plasma apoE . In the nervous system, apoE mRNA is present in neurons, astrocytes, ependymal cells, nonmyelinating Schwann cells, but not in microglia, oligodendroglia, choroidal cells, or myelinating Schwann cells. ApoE produced by mammalian cells exists in different forms, monomers, dimers, modified, unmodified, lipid-rich, and lipid-poor, and so forth. ApoE plays a double-role in immune responses. Both apoE containing lipoproteins and multimers of synthetic apoE peptides inhibited proliferation of cultured lymphocytes by inhibiting DNA synthesis and reducing phospholipid turnover in T cells. ApoE can also affect innate and acquired immune responses in vitro by its ability to suppress stimulation of cultured neutrophils. ApoE can bind lipopolysaccharide (LPS), attenuate the inflammatory response, and thus reduce LPS induced lethality. Injection of LPS stimulated higher expression of inflammatory cytokines like interleukin (IL) -1β, IL-12, and interferon-γ (IFN-γ), as well as IL-6.

A DNA sequence encoding the human APOE (P02649) (Lys 19-His 317) was fused with a Trx tag at the N-terminus. The purified protein was biotinylated in vitro.

At Leading Biology, the biological activity of a recombinant protein is routinely measured using a bioassay, e.g. chemotaxis or cell proliferation assay, enzyme assay, or a functional ELISA. When a recombinant protein is an enzyme, specific activity is derived from an enzymatic assay. Each enzyme is tested for potency by cleavage of a substrate. We are in the process of updating the biological activity data. If you have any questions regarding this update, please feel free to contact our technical support team.

Lyophilized from sterile PBS, pH 7.4. Please contact us for any concerns or special requirements. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween 80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hard copy of CoA.

In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature. Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise. Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.