Characterization of a specific phorbol ester aporeceptor in mouse brain cytosol
| Autor: | Karen L. Leach, Peter M. Blumberg, Margaret L. James |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Receptors
Drug Receptors Cell Surface Binding Competitive Mice chemistry.chemical_compound Cytosol Phorbol Esters Animals Phosphatidylinositol Binding site Caenorhabditis elegans Proteins Phorbol 12 13-Dibutyrate Protein Kinase C Protein kinase C Phosphatidylethanolamine Multidisciplinary Chemistry Brain Phosphatidylserine Phosphatidic acid Phorbols Dissociation constant Kinetics Biochemistry Carcinogens Phorbol Female Apoproteins Carrier Proteins Research Article |
| Zdroj: | Proceedings of the National Academy of Sciences. 80:4208-4212 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.80.14.4208 |
| Popis: | In the presence of phosphatidylserine, [20-3H]-phorbol 12,13-dibutyrate [( 3H]PBt2) bound specifically to a single class of binding sites in mouse brain cytosol (supernatant at 100,000 X g). The dissociation constant for binding was 3.1 X 10(-9) M, and at saturation 23.2 pmol of [3H]PBt2 was bound per mg of cytosolic protein. Less than 1 pmol of [3H]PBt2 per mg bound in the absence of phospholipids. Phosphatidic acid, sphingomyelin, and phosphatidylinositol also were able to reconstitute binding activity, whereas phosphatidylcholine and phosphatidylethanolamine were relatively ineffective. [3H]PBt2 binding was inhibited by phorbol 12-myristate 13-acetate (Ki = 4.4 X 10(-11) M), phorbol 12,13-didecanoate (Ki = 7.7 X 10(-9) M), phorbol 12,13-diacetate (Ki = 4.4 X 10(-7) M) and 4-O-methylphorbol 12-myristate 13-acetate (Ki = 5.1 X 10(-7) M). The apparent Ki values of the phorbol-related diterpenes for inhibiting binding agreed reasonably closely with the values previously determined for mouse brain membrane binding. The biologically inactive derivatives phorbol (30 microM) and 4 alpha-phorbol 12,13-didecanoate (30 microM) did not inhibit binding. The aporeceptor was eluted in one peak during Ultrogel 44 column chromatography, corresponding to a molecular weight of approximately equal to 77,000. Calcium phospholipid-dependent protein kinase C activity was eluted with a profile similar to that of the cytosolic aporeceptor-binding activity. |
| Databáze: | OpenAIRE |
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