Crosslinking of HCG to its Specific Receptor of Porcine Ovarian Membrances

Summary

HCG receptors of porcine ovarian plasma membranes were loaded with ¹²⁵I-hCG and covalently crosslinked with glutaraldehyde. The plasma membranes were labeled with tritium. The hCG receptor complex was solubilized in 1% SDS and subsequently chromatographed on Biogel P 300. 40-50% of ¹²⁵I-radioactivity eluted near the void volume. ³H radioactivity in these fractions indicated the presence of crosslinked hormone receptor complexes. A second minor peak of ¹²⁵I-radioactivity appeared at 55000 d. A third peak represented subunits of ¹²⁵I-hCG. Analysis of the Biogel P 300 purified ¹²⁵I-hCG receptor complex by polyacrylamid gel electrophoresis in sodium dodecyl sulfate resulted in two radioactivity peaks. The main peak corresponded to 90 000-100 000 d, the second peak was calculated to approximately 140 000 d. As a result the majority of the hormone receptor complex has a molecular weight of 90 000-100 000 d. Existence of subunits is discussed

Key-Words:

Porcine Ovaries - HCG Receptor - Glutaraldehyde Crosslinking - Molecular Weight of the Hormone Receptor Complex