HCG

HCG is a glycoprotein hormone built from two non-covalently associated subunits. The alpha subunit is shared with LH, FSH and TSH; the beta subunit is unique to hCG and is what determines specificity at the LH/hCG receptor. Both chains carry N- and O-linked glycans, and that carbohydrate is functionally significant rather than decorative — it is the reason the material is quantified in international units of biological activity rather than by mass alone.

Shipped as a lyophilized powder in a sealed glass vial at 5,000 IU, kept dry until a laboratory reconstitutes it. Glycoproteins of this size are more sensitive to heat and to repeated freeze-thaw than short synthetic peptides. Supplied for laboratory research use only.

HCG appears in the literature mainly as a receptor ligand and as an assay reference material. Areas of study include:

• LH/hCG receptor pharmacology — binding, activation and desensitization at this class A GPCR, and the structural basis of cross-reactivity with LH.
• Subunit assembly — how the alpha and beta chains associate and what happens to activity when they do not.
• Glycosylation heterogeneity — isoform variation between preparations and its effect on measured potency and half-life.
• Immunoassay development, where hCG is among the most characterized analytes in clinical chemistry.
• Bioassay standardization — why IU and mass figures do not convert cleanly between sources.

Supplied as a characterized reagent. We make no claim about effects in any organism.