Erythropoietin
Glycoprotein hormone that stimulates red blood cell production through EPO receptor activation on erythroid progenitor cells.
Chemical Identity
| Property | Value |
|---|---|
| Molecular Weight | ~34 kDa (glycosylated) |
| Gene | EPO |
| Amino Acids | 165 (mature protein) |
| Glycosylation | 4 N-linked, 1 O-linked |
| Disulfide Bonds | 2 |
Structure
Erythropoietin (EPO) is a 165-amino acid glycoprotein hormone with ~40% carbohydrate content. It contains four N-glycosylation sites (Asn24, Asn38, Asn83, Asn126) and one O-glycosylation site (Ser126). The protein core has a four-helix bundle structure stabilized by two disulfide bonds.
Mechanism of Action
EPO binds EPO receptors (EPOR) on erythroid progenitor cells in bone marrow, activating JAK2/STAT5 signaling. This promotes survival, proliferation, and differentiation of erythroid precursors (CFU-E, proerythroblasts), ultimately increasing red blood cell production. EPO also has tissue-protective effects in brain and heart.
Clinical Applications
- Anemia of chronic kidney disease: Standard treatment (epoetin alfa, darbepoetin)
- Chemotherapy-induced anemia: Reduction of transfusion requirements
- Anemia of prematurity: In premature infants
- Autologous blood donation: EPO-enhanced blood collection
Pharmacology
- Half-life: 4-13 hours (endogenous), varies by formulation
- Recombinant forms: Epoetin alfa, darbepoetin alfa, methoxy PEG-epoetin beta
- Route: IV, SC
- Target Hgb: 10-12 g/dL (avoid >13 g/dL)
References
- Winearls, C.G., et al. (1986). Recombinant human erythropoietin for anaemia in renal failure. Lancet, 2, 1175-1178.
- Singh, A.K., et al. (2006). CHOIR trial: high hemoglobin target in CKD. New England Journal of Medicine, 355, 2085-2098.
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