Apolipoprotein E Human ELISA

Summary

Circulating human apoE (apolipoprotein E) is a single-chain protein of 34.2 kDa, encoded by single gene. ApoE is initially synthetised as a propeptide of 317 amino acid residues. After post-translational cleavage of a signal peptide of 18 amino acids, the mature protein consists of 299 amino acids. The human apoE gene is polymorphic, with three common alleles (epsilon2, epsilon3, epsilon4) coding for three isoforms (E2, E3, E4). The molecular basis of this polymorphism is cystein-arginine interchange. This polymorphism leads to the presence of six different phenotypes in the human population: three homozygous and three heterozygous. ApoE is produced in various organs, including kidney, adrenal glands, gonads and spleen, but mainly in liver. The second largest production of ApoE is found in the brain. It has many functions in the body. When it is synthetised by the liver as part of VLDL it functions in the transport of triglycerides to the liver tissue. It is incorporated into HDL (as HDL-E) and functions in cholesterol distribution among cells. It is also incorporated into intestinally synthetised chylomicrons and transports dietary triglycerides and cholesterol. ApoE is involved in lipid metabolism by mediating the receptor binding of apoE lipoproteins to the LDL receptor. Other functions and properties ascribed to apoE include its role in immunoregulation, inflammatory response, nerve regeneration, inhibition of endothelial and tumor cell proliferation. ApoE plays a significant role in the pathogenesis of atherosclerosis. One of the functions suggested for apoE is based on observations that apoE is found in amyloid plaques associated with Alzheimer´s and Creutzfeldt-Jakob diseases, as well as in a variety of types of cerebral and systemic amyloidoses.

Features

• It is intended for research use only
• The total assay time is less than 3.5 hours
• The kit measures apoE in serum, plasma (EDTA, citrate, heparin) and cerebrospinal fluid
• Assay format is 96 wells
• Quality Controls are human serum based
• Standard is native protein based
• Components of the kit are provided ready to use, concentrated or lyophilized

Research topic

Lipoprotein metabolism, Neural tissue damage markers

Assay format

Sandwich ELISA, Biotin-labelled antibody

Applications

Cerebrospinal fluid, Plasma-Citrate, Plasma-EDTA, Plasma-Heparin, Serum

Sample requirements

5 µl/well

Storage/Shipping

2 – 8°C

Calibration Curve

Calibration range

1 to 64 ng/ml

Limit of detection

0.3 ng/ml

Intra-assay (Within-Run, n=8)

CV = 4.8%

Inter-assay (Run-to-Run, n=6)

CV = 8.9%

Spiking Recovery

95.4%

Dilution Linearity

104.6%

Cross-Reactivity

References to summary

• Blennow K, Davidsson P, Andreasen N, Minthon L, Fredman P, Larsson H, Hesse C. Measurement of apolipoprotein E (apoE) in cerebrospinal fluid. Neurochem Res. 2000 Apr;25 (4):511-7
• Cibickova L, Palicka V. Alzheimerova choroba, cholesterol a apolipoprotein E – nove souvislosti. Klin Biochem Metab . 2005;13(34):127-130
• Glisic S, Alavanatic D, Stankovic S. The effect of a gender difference in the apolipoprotein E gene DNA polymorphism on serum lipid levels in a Serbian healthy population. Clin Chem Lab Med. 2000 Jun;38 (6):539-44
• Gueguen R, Bohnet K, Vincent-Viry M, Schiele F, Siest G, Visvikis S. Biological variations and genetic reference values for apolipoprotein E serum concentrations: results from the STANISLAS cohort study. Clin Chem. 1998 May;44 (5):957-65
• Kattan OM, Kasravi FB, Elford EL, Schell MT, Harris HW. Apolipoprotein E-mediated immune regulation in sepsis. J Immunol. 2008 Jul 15;181 (2):1399-408
• Kuiper J, Van Berkel TJ, Van Oosten M, Rensen PC, Van Eck M, Van Amersfoort ES, Van Dam AM, Breve JJ, Vogel T, Panet A. Apolipoprotein E protects against bacterial lipopolysaccharide-induced lethality. A new therapeutic approach to treat gram-negative sepsis. J Biol Chem. 2001 Mar 23;276 (12):8820-4
• Schiele F, Siest G, Visvikis A, Herbeth B, Vincent-Viry M. Effect of short- and long-term storage on human serum and recombinant apolipoprotein E concentration. Clin Chem Lab Med. 2000 Jun;38 (6):525-8

By research topic:

• Lipoprotein metabolism
• Neural tissue damage markers

By molecule:

• Apolipoprotein E

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