Structure
FSH is a glycoprotein. Each monomeric unit is a protein molecule with a sugar attached to it; two of these make the full, functional protein. Its structure is similar to those of LH, TSH, and hCG. The protein dimer contains 2 polypeptide units, labeled alpha and beta subunits. The alpha subunits of LH, FSH, TSH, and hCG are identical, and contain 92 amino acids. The beta subunits vary. FSH has a beta subunit of 111amino acids (FSH β), which confers its specific biologic action and is responsible for interaction with the FSH-receptor. The sugar part of the hormone is composed of fucose, galactose, mannose, galactosamine, glucosamine, and sialic acid, the latter being critical for its biologic half-life. The half-life of FSH is 3–4 hours.
The 92-amino-acid-long FSH alpha subunit in humans has the following sequence:
NH2 – Ala – Pro – Asp – Val – Gln – Asp – Cys – Pro – Glu – Cys – Thr – Leu – Gln – Glu – Asn – Pro – Phe – Phe – Ser – Gln – Pro – Gly – Ala – Pro – Ile – Leu – Gln – Cys – Met – Gly – Cys – Cys – Phe – Ser – Arg – Ala – Tyr – Pro – Thr – Pro – Leu – Arg – Ser† – Lys – Lys – Thr – Met – Leu – Val – Gln – Lys – Asn – Val – Thr – Ser – Glu – Ser – Thr – Cys – Cys – Val – Ala – Lys – Ser – Tyr – Asn – Arg – Val – Thr – Val – Met – Gly – Gly – Phe – Lys – Val – Glu – Asn – His – Thr – Ala – Cys – His – Cys – Ser – Thr – Cys – Tyr – Tyr – His – Lys – Ser – OH
- Note: The carbohydrate moiety is linked to the asparagine at positions 52 and 78.
The 111-amino-acid-long FSH beta subunit in humans has the following sequence:
NH2 – Asn – Ser – Cys – Glu – Leu – Thr – Asn – Ile – Thr – Ile – Ala – Ile – Glu – Lys – Glu – Glu – Cys – Arg – Phe – Cys – Ile – Ser – Ile – Asn – Thr – Thr – Trp – Cys – Ala – Gly – Tyr – Cys – Tyr – Thr – Arg – Asp – Leu – Val – Tyr – Lys – Asp – Pro – Ala – Arg – Pro – Lys – Ile – Gln – Lys – Thr – Cys – Thr – Phe – Lys – Glu – Leu – Val – Tyr – Glu – Thr – Val – Arg – Val – Pro – Gly – Cys – Ala – His – His – Ala – Asp – Ser – Leu – Tyr – Thr – Tyr – Pro – Val – Ala – Thr – Gln – Cys – His – Cys – Gly – Lys – Cys – Asp – Ser – Asp – Ser – Thr – Asp – Cys – Thr – Val – Arg – Gly – Leu – Gly – Pro – Ser – Tyr – Cys – Ser – Phe – Gly – Glu – Met – Lys – Glu – OH
- Note: The carbohydrate moiety is linked to the asparagine at positions 7 and 24.
Read more about this topic: Follicle-stimulating Hormone
Famous quotes containing the word structure:
“A committee is organic rather than mechanical in its nature: it is not a structure but a plant. It takes root and grows, it flowers, wilts, and dies, scattering the seed from which other committees will bloom in their turn.”
—C. Northcote Parkinson (1909–1993)
“There is no such thing as a language, not if a language is anything like what many philosophers and linguists have supposed. There is therefore no such thing to be learned, mastered, or born with. We must give up the idea of a clearly defined shared structure which language-users acquire and then apply to cases.”
—Donald Davidson (b. 1917)
“For the structure that we raise,
Time is with materials filled;
Our to-days and yesterdays
Are the blocks with which we build.”
—Henry Wadsworth Longfellow (1809–1882)