Apolipoproteins are protein components of plasma lipoproteins. The human apoA-I gene encodes a single chain, 243 amino acid protein which promotes cholesterol efflux from tissues to the liver for excretion. Apolipoprotein A-I is the major protein component of high density lipoprotein (HDL) in the plasma. It can function as a co-factor for lecithin cholesterolacyltransferase (LCAT), which is responsible for the formation of most plasma cholesterylesters. The human apoA-II gene encodes the second most abundant protein of HDL particles, where it influences plasma levels of free fatty acids (FFA). The human apoA-IV gene encodes a 396 amino acid preprotein, which after proteolytic processing is secreted from the intestine in association with chylomicron particles. ApoA-IV is a potent activator of LCAT in vitro. The human apoA-V gene encodes a 366 amino acid protein that is believed to be an important determinant of plasma triglyceride levels.
Background References
1. Su M et al. Expression and purification of recombinant human apolipoprotein A-II in Pichia pastoris. Assay Drug Dev Technol 11:501-507 (2013).
2. Lux S E et al. Isolation and characterization of the tryptic and cyanogen bromide peptides of apoLp-Gln-II (apoA-II), plasma high density apolipoprotein. J Biol Chem 247:7519-7527 (1972).
Sequence Similarity
Belongs to the apolipoprotein A2 family.
Tissue Specificity
Plasma; synthesized in the liver and intestine.
Post-translational Modification
Phosphorylation sites are present in the extracellular medium.; Apolipoprotein A-II is O-glycosylated.
Western blot analysis of Apolipoprotein A II on human plasma lysates with Rabbit anti-Apolipoprotein A II antibody (ET7107-47) at 1/1,000 dilution.
Lysates/proteins at 10 µg/Lane.
Predicted band size: 11 kDa Observed band size: 14 kDa
Exposure time: 1 minute; ECL: K1801;
4-20% SDS-PAGE gel.
Proteins were transferred to a PVDF membrane and blocked with 5% NFDM/TBST for 1 hour at room temperature. The primary antibody (ET7107-47) at 1/1,000 dilution was used in 5% NFDM/TBST at 4℃ overnight. Goat Anti-Rabbit IgG - HRP Secondary Antibody (HA1001) at 1/50,000 dilution was used for 1 hour at room temperature.
☑ Relative expression (RE)
Immunocytochemistry analysis of HepG2 (positive) and A549 (negative) labeling Apolipoprotein A II with Rabbit anti-Apolipoprotein A II antibody (ET7107-47) at 1/3,000 dilution.
Cells were fixed in 4% paraformaldehyde for 15 minutes at room temperature, permeabilized with 0.1% Triton X-100 in PBS for 15 minutes at room temperature, then blocked with 1% BSA in 10% negative goat serum for 1 hour at room temperature. Cells were then incubated with Rabbit anti-Apolipoprotein A II antibody (ET7107-47) at 1/3,000 dilution in 1% BSA in PBST overnight at 4 ℃. Goat Anti-Rabbit IgG H&L (iFluor™ 488, HA1121) was used as the secondary antibody at 1/1,000 dilution. PBS instead of the primary antibody was used as the secondary antibody only control. Nuclear DNA was labelled in blue with DAPI.
Beta tubulin (HA601187, red) was stained at 1/100 dilution overnight at +4℃. Goat Anti-Mouse IgG H&L (iFluor™ 594, HA1126) was used as the secondary antibody at 1/1,000 dilution.
Immunohistochemical analysis of paraffin-embedded human liver tissue with Rabbit anti-Apolipoprotein A II antibody (ET7107-47) at 1/1,000 dilution.
The section was pre-treated using heat mediated antigen retrieval with Tris-EDTA buffer (pH 9.0) for 20 minutes. The tissues were blocked in 1% BSA for 20 minutes at room temperature, washed with ddH2O and PBS, and then probed with the primary antibody (ET7107-47) at 1/1,000 dilution for 1 hour at room temperature. The detection was performed using an HRP conjugated compact polymer system. DAB was used as the chromogen. Tissues were counterstained with hematoxylin and mounted with DPX.
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