Human chorionic gonadotropin (hCG) is a glycoprotein hormone composed of two non-identical subunits: an alpha subunit and a beta subunit.
Here's a more detailed breakdown:
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Alpha Subunit: This subunit contains 92 amino acids. Notably, this alpha subunit is identical to the alpha subunits found in other glycoprotein hormones such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH).
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Beta Subunit: This subunit contains 145 amino acids and is unique to hCG. This uniqueness is what gives hCG its specific biological activity and distinguishes it from the other glycoprotein hormones that share the same alpha subunit.
In summary, hCG is a dimer comprised of the 92 amino acid alpha subunit (common to LH, FSH, and TSH) and the 145 amino acid beta subunit (unique to hCG). The beta subunit gives hCG its distinct function.
