Compound monograph
hCG (Human chorionic gonadotropin)
Human chorionic gonadotropin (hCG) is a glycoprotein hormone made of two different subunits, alpha and beta, that associate without a covalent bond between the chains. This record describes the intact two-chain hormone. It is not a record of either subunit alone or of any fragment.
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Identity & nomenclature
Human chorionic gonadotropin (hCG) is a glycoprotein hormone made of two different subunits, alpha and beta, that associate without a covalent bond between the chains. This record describes the intact two-chain hormone. It is not a record of either subunit alone or of any fragment.
“hCG” on its own does not specify a preparation, a glycoform or a subunit. Names of the individual subunits, and of the genes that encode them, are not names of the intact hormone and are not aliases of this record.
Canonical name: Human chorionic gonadotropin.
Declared aliases and development codes: hCG.
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Molecular properties
Molecular formula, mass, sequence and registry identifiers are not listed for this record. The sources reviewed did not meet the two-source verification standard used in this library.
Two chains, described separately and never joined into one string. Alpha subunit: the cDNA encodes a 24-amino-acid presequence (Fiddes and Goodman, 1979), and protein sequencing reported a 92-residue chain in which a fraction of the chains lacked the first two or three residues (Morgan et al., 1975). The two crystal-structure depositions differ at alpha position 4: PDB entry 1HRP records threonine and PDB entry 1HCN records valine. Beta subunit: the cDNA encodes a 145-amino-acid chain with a 20-amino-acid presequence (Fiddes and Goodman, 1980), while an earlier protein-sequencing report described 147 residues (Carlsen et al., 1973). No single sequence is recorded here because these sources have not been reconciled.
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Structural characteristics
Wu et al. (1994) and Lapthorn et al. (1994) each report a crystal structure in which both subunits have a cystine-knot fold. Wu et al. determined theirs on recombinant selenomethionyl protein after partial deglycosylation, so that material is not the fully glycosylated native hormone.
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Molecular targets & mechanisms
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Analytical considerations
No molecular formula or molecular mass is recorded. hCG is glycosylated, the attached glycans vary between preparations, and the chain descriptions above are not reconciled, so a single calculated value would describe no particular material.
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Verified bibliography
- Human chorionic gonadotropin. Linear amino acid sequence of the beta subunit.
Carlsen RB, Bahl OP, Swaminathan N
The Journal of biological chemistry · 1973-10-10 · Journal Article
current - The amino acid sequence of human chorionic gonadotropin. The alpha subunit and beta subunit.
Morgan FJ, Birken S, Canfield RE
The Journal of biological chemistry · 1975-07-10 · Journal Article
current - Isolation, cloning and sequence analysis of the cDNA for the alpha-subunit of human chorionic gonadotropin.
Fiddes JC, Goodman HM
Nature · 1979-10-04 · Journal Article
current - The cDNA for the beta-subunit of human chorionic gonadotropin suggests evolution of a gene by readthrough into the 3'-untranslated region.
Fiddes JC, Goodman HM
Nature · 1980-08-14 · Journal Article
current - Structure of human chorionic gonadotropin at 2.6 A resolution from MAD analysis of the selenomethionyl protein.
Wu H, Lustbader JW, Liu Y, Canfield RE, Hendrickson WA
Structure (London, England : 1993) · 1994-06-15 · Journal Article
current - Crystal structure of human chorionic gonadotropin.
Lapthorn AJ, Harris DC, Littlejohn A, Lustbader JW, Canfield RE, Machin KJ, Morgan FJ, Isaacs NW
Nature · 1994-06-09 · Journal Article
current
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Methodology & citation verification
Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.
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