Recombinant Human Apolipoprotein M Protein, CF

• Reactivity: Hu
• Applications: Bioactivity
• Format: Carrier-Free

Recombinant Human Apolipoprotein M Protein, CF Summary

• Details of Functionality: Measured by its ability to bind all-trans-retinoic acid. The concentration of all-trans-retinoic acid required to quench 50% of Trp fluorescence in Recombinant Human Apolipoprotein M/ApoM is approximately 10-50 μM.
• Source: E. coli-derived human Apolipoprotein M/ApoM protein
  Cys23-Asn188, with an N-terminal Met and 6-His tag
• Accession #: NP_061974
• N-terminal Sequence: Met & Thr62
• Protein/Peptide Type: Recombinant Proteins
• Gene: APOM
• Purity: >95%, by SDS-PAGE under reducing conditions and visualized by silver stain
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 19.5 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 19-21 kDa, reducing conditions

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS.
• Purity: >95%, by SDS-PAGE under reducing conditions and visualized by silver stain
• Reconstitution Instructions: Reconstitute at 500 μg/mL in PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Human Apolipoprotein M Protein, CF

• Apolipoprotein M
• APOM
• apo-M
• G3A
• HSPC336
• MGC22400
• NG20
• NG20-like protein
• Protein G3a

Background

Apolipoprotein M (ApoM) is an approximately 25 kDa variably glycosylated protein that adopts a beta-barrel structure characteristic of lipocalin family proteins. It functions as a component of lipoprotein particles which play essential roles in fatty acid and cholesterol transport and metabolism (1, 2). Human ApoM shares 83% amino acid sequence identity with mouse and rat ApoM (3). Alternative splicing generates a short isoform that lacks the N-terminal 72 amino acids. ApoM is produced primarily by hepatocytes but also by renal tubule epithelial cells (4). The signal peptide is not cleaved and is required for ApoM association with lipoprotein particles as well as Megalin mediated reabsorption by the kidney (5, 6). ApoM is cleared from the circulation by the ubiquitously expressed LDL R (7, 8). The majority of circulating ApoM is associated with HDL, while a smaller fraction is associated with LDL (3, 9, 10). It promotes the intracellular formation of large pre-beta (discoidal) HDL particles which inhibit the development of atherosclerotic plaques by facilitating the efflux of cellular cholesterol and preventing phospholipid oxidation (7, 9, 11‑13). The lipocalin structure of ApoM enables it to function as a carrier protein for small hydrophobic molecules including retinol (Vitamin A), all-trans-retinoic acid, 9-cis-retinoic acid, and sphingosine-1-phosphate (S1P) (14, 15). ApoM delivers S1P to S1P₁ receptors and contributes to the maintenance of vascular endothelial integrity (15).

1. Christoffersen, C. and L.B. Nielsen (2013) Curr. Opin. Lipidol. May 6 Epub. PMID 23652568.
2. Arkensteijn, B.W. et al. (2013) Int. J. Mol. Sci. 14:4419.
3. Xu, N. and B. Dahlback (1999) J. Biol. Chem. 274:31286.
4. Zhang X.Y. et al. (2003) Acta Histochem. 105:67.
5. Christoffersen, C. et al. (2008) J. Biol. Chem. 283:18765.
6. Faber, K. et al. (2006) Mol. Endocrinol. 20:212.
7. Christoffersen, C. et al. (2010) Circ. Res. 106:1624.
8. Christoffersen, C. et al. (2012) J. Lipid Res. 53:2198.
9. Christoffersen, C. et al. (2008) J. Biol. Chem. 283:1839.
10. Christoffersen, C. et al. (2006) J. Lipid Res. 47:1833.
11. Mulya, A. et al. (2010) J. Lipid Res. 51:514.
12. Wolfrum, C. et al. (2005) Nat. Med. 11:418.
13. Elsoe, S. et al. (2012) Atherosclerosis 221:91.
14. Ahnstrom, J. et al. (2007) J. Lipid Res. 48:1754.
15. Christoffersen, C. et al. (2011) Proc. Natl. Acad. Sci. USA 108:9613.

Publications for Apolipoprotein M/ApoM (4550-AM)(2)

Publications using 4550-AM

• H Mousa, A Thanassoul, SM Zughaier ApoM binds endotoxin contributing to neutralization and clearance by High Density Lipoprotein Biochemistry and Biophysics Reports, 2023-02-28;34(0):101445. 2023-02-28 [PMID: 36915826] (Bioassay, Human)
• R Terao, M Honjo, M Aihara Apolipoprotein M Inhibits Angiogenic and Inflammatory Response by Sphingosine 1-Phosphate on Retinal Pigment Epithelium Cells Int J Mol Sci, 2017-12-31;19(1):. 2017-12-31 [PMID: 29301231] (Bioassay, Human)

Bioinformatics

• Gene Symbol: APOM
• Uniprot:
  • NP_061974()