Expression, purification and characterization of human chorionic gonadotropin produced in suspension-cultured CHO cells.

Human chorionic gonadotropin (hCG) is a 237-amino acid glycoprotein hormone with a regular glycoform weighing approximately 37,180 Da. This hormone is physiologically produced by syncytiotrophoblastic cells of placental villi during pregnancy, where it stimulates progesterone production and maintains the corpus luteum in the first 6 weeks of gestation while the placenta develops. It is also well-established that high levels of β-hCG are associated with tumor malignancy and may play a significant role in non-germ cell tumors. hCG, like FSH, LH, and TSH hormones, is a heterodimeric protein composed of two subunits: the α subunit shared with the aforementioned hormones, and the β subunit that confers specific characteristics to each hormone.