Intersubunit disulfides of the follitropin receptor
The electrophoretic mobility of radioiodinated follitropin (FSH) alpha and beta subunits as well as the alpha beta dimer changed markedly depending on the concentration of reducing agents such as dithiothreitol. The changes were more dramatic in the beta subunit than in the alpha subunit. SVI-FSH, was cross-linked with a cleavable (nondisulfide) homobifunctional reagent and electrophoresed. The cross-linked sample revealed three bands of high molecular mass, in addition to the hormone subunit and dimer bands. The band of lightest mass, 110 kDa, was the major band and the other two of 76 and 62 kDa were barely noticeable. Upon reduction with dithiothreitol, the 110-kDa band decreased while the 76- and 62-kDa bands increased, indicating the existence of disulfides between components of the 110-kDa complex. Complex formation was independent of blocking free sulfhydryl groups with N-ethylmaleimide. When the cross-linked complexes were reduced in the gel matrix and analyzed on fresh gels, the 76- and 62-kDa complexes were generated from the 110-kDa band, indicating the loss of two components. The lost components were estimated to be at 14 and 34 kDa. The rate of formation and cleavage of the cross-linked complexes indicated a sequential and incremental addition of 22-, 14-, and 34-kDa components to the FSH alpha beta dimer. The results of reduction of the cross-linked complexes demonstrate the existence of disulfide linkage between the three components.
- Research Organization:
- Univ. of Wyoming, Laramie
- OSTI ID:
- 6257949
- 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
DISULFIDES
CROSS-LINKING
ELECTROPHORESIS
RADIORECEPTOR ASSAY
FSH
BIOCHEMISTRY
RECEPTORS
CONFIGURATION INTERACTION
IODINE 125
MOLECULAR STRUCTURE
SWINE
ANIMALS
BETA DECAY RADIOISOTOPES
CHEMICAL REACTIONS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
GONADOTROPINS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
POLYMERIZATION
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques