Target Information

Erythropoietin (EPO) is the central hormone responsible for regulating erythropoiesis. This glycoprotein, also known as hematopoietin, is primarily synthesized in the kidneys and, to a lesser extent, the liver in response to hypoxic conditions, where it stimulates red blood cell production. Human EPO consists of 166 amino acids and has a predicted molecular mass of about 18 kDa, though it typically appears at 35–55 kDa on SDS‑PAGE due to extensive glycosylation. It shares significant structural similarity with thrombopoietin (TPO), exhibiting 44% amino acid homology. EPO is highly conserved evolutionarily, with human and mouse EPO sharing 80% identity, and mouse and rat EPO sharing 95% identity.
EPO exerts its biological activity by binding to the homodimeric EPO receptor (EPOR) on erythroid progenitor cells, driving their differentiation and maturation. Circulating EPO levels rise in response to conditions that cause tissue hypoxia, such as hemorrhage, high‑altitude exposure, cardiopulmonary disorders, or anemia. Elevated EPO may also result from ectopic production by certain liver and kidney tumors. Conversely, reduced EPO levels are commonly associated with chronic kidney disease, chronic inflammatory conditions, or chemotherapy-induced anemia. Endogenous human EPO and recombinant EPO possess identical amino acid sequences, differing only in their glycosylation patterns.