Composition of cross-linked 125I-follitropin-receptor complexes
Both of the alpha and beta subunits of intact human follitropin (FSH) were radioiodinated with SVI-sodium iodide and chloramine-T and could be resolved on sodium dodecyl sulfate-polyacrylamide gels. Radioiodinated FSH was affinity-cross-linked with a cleavable (nondisulfide) homobifunctional reagent to its membrane receptor on the porcine granulosa cell surface as well as to a Triton X-100-solubilized form of the receptor. Cross-linked samples revealed three additional bands of slower electrophoretic mobility, corresponding to 65, 83, and 117 kDa, in addition to the hormone bands. The hormone alpha beta dimer band corresponded to 43 kDa. Formation of the three bands requires the SVI-hormone to bind specifically to the receptor with subsequent cross-linking. Binding was prevented by an excess of the native hormone but not by other hormones. A monofunctional analog of the cross-linking reagent failed to produce the three bands. Reagent concentration-dependent cross-linking revealed that their formation was sequential; smaller complexes formed first and then larger ones. When gels of cross-linked complexes were treated to cleave covalent cross-links and then electrophoresed in a second dimension, 18-, 22-, and 34-kDa components were released, in addition to the alpha and beta subunits of the hormone.
- Research Organization:
- Univ. of Wyoming, Laramie
- OSTI ID:
- 6257968
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 23
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
FSH
CROSS-LINKING
RADIORECEPTOR ASSAY
RECEPTORS
ELECTROPHORESIS
IODINE 125
MOLECULAR WEIGHT
POLYETHYLENE GLYCOLS
SOLUBILITY
SWINE
ALCOHOLS
ANIMALS
BETA DECAY RADIOISOTOPES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
GLYCOLS
GONADOTROPINS
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PEPTIDE HORMONES
PITUITARY HORMONES
POLYMERIZATION
POLYMERS
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques