J. Biol. Chem., Vol. 265, Issue 10, 5494-5503, 04, 1990
Purification of follitropin receptor from bovine calf testes
B Dattatreyamurty, SB Zhang and LE Reichert Jr
Department of Biochemistry, Albany Medical College, New York 12208.
Follitropin (FSH) receptors were solubilized from pure light membranes of
bovine calf testis, using an optimum detergent to protein ratio of 0.01.
The soluble FSH receptor fraction was gel filtered through Sepharose 6B to
isolate an active fraction (6B-Fr-1) which behaved as a complex of FSH
receptor and Gs protein. The 6B-Fr-1 was concentrated by ultrafiltration
and further purified by sequential Sepharose 4B gel filtration,
DEAE-cellulose chromatography (to separate the receptor from Gs protein),
and wheat germ lectin affinity chromatography. The purified receptor had an
FSH-binding capacity of approximately 3.47 nmol/mg of protein with a Kd of
1.9 X 10(-10) M. Yield was 526 micrograms/11.5 kg tested. Radioiodinated,
as well as unlabeled purified FSH receptor, migrated on sodium dodecyl
sulfate- polyacrylamide gels as a single major band of Mr approximately
240,000. This band was not affected by 8 M urea treatment prior to analysis
by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but treatment
with dithiothreitol induced the loss of the 240-kDa band, with appearance
of an Mr approximately 60,000 band. The availability of highly purified,
stable FSH receptor should allow direct studies on its structure-function
relationships.