Characterization by photoaffinity labeling of a steroid binding protein in rat liver plasma membrane
| Autor: | Jose M. Macarulla, Ana Alejandro, Miguel Trueba, Aida Marino, M. J. Sancho, Iñaki Ibarrola |
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| Rok vydání: | 1992 |
| Předmět: |
Male
Hydrocortisone Physiology medicine.medical_treatment Biophysics Peptide Levonorgestrel Binding Competitive Promegestone Steroid medicine Centrifugation Density Gradient Animals Binding site Receptor Desoxycorticosterone Progesterone chemistry.chemical_classification Binding Sites Photoaffinity labeling Binding protein Cell Membrane Affinity Labels Rats Inbred Strains Cell Biology Rats Cytosol Steroid hormone Biochemistry chemistry Liver Electrophoresis Polyacrylamide Gel Receptors Progesterone |
| Zdroj: | The Journal of membrane biology. 125(2) |
| ISSN: | 0022-2631 |
| Popis: | The mechanism of steroid uptake by the cell remains controversial. [3H]R5020 was utilized to characterize by photoaffinity labeling the steroid binding site in plasma membrane. This binding was saturable, reversible and had one type of binding site (K d = 33 ± 4 nm, B max = 32 ± 2 pmol/mg). [3H]R5020 could be prevented from binding by a variety of steroids (cortisol, progesterone, deoxycorticosterone, and levonorgestrel); estradiol did not have affinity for this binding site. The kinetics of R5020 photoactivation was time dependent and saturable. SDS-PAGE showed a specific band which corresponded to a 53-kDa peptide. The sucrose density gradient analysis has revealed the existence of a protein with a sedimentation coefficient of 3.6 ± 0.2 S. This polypeptide shows different characteristics than cytosolic steroid receptor or serum steroid binding proteins. This binding protein could correspond to the steroid binding site previously found in the plasma membrane. |
| Databáze: | OpenAIRE |
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