Abstract |
Electron paramagnetic resonance (EPR) spectra were measured for the spin labelled phorbol-12,13-diester [5,6]PA bound to membranes of the particulate fraction of mouse brain tissue rich in PKC receptors. [5,6]PA is a bioactive derivative of the potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), carrying the spin label in a doxyl group in position 7' of the 12-O-tetradecanoyl residue. A mathematical model based on special algorithms (Griffith, O.H. and Jost, P.C. Spin labeling: theory and applications, 1976) allows a satisfactory reconstruction of the experimental spectrum. It reveals that in the experimental spectrum the signal from the [5,6]PA molecules bound non-specifically to the lipid bilayer of the membranes is superimposed by the signal of [5,6]PA molecules bound specifically, i.e. to the active site of PKC (approximately 10% of total EPR signal intensity). Moreover, interpretation of spectral parameters indicates that in [5,6]PA molecules bound specifically the tetradecanoyl chain exhibits a larger motional freedom compared to that in [5,6]PA bound non-specifically. These new findings are in accordance with views featured independently by two recent molecular models of interaction of PKC with cellular membranes (8,9).
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Authors | J Svetek, M Schara, S Pecar, M Hergenhahn, E Hecker |
Journal | Carcinogenesis
(Carcinogenesis)
Vol. 16
Issue 10
Pg. 2589-92
(Oct 1995)
ISSN: 0143-3334 [Print] England |
PMID | 7586171
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- (5,6)PA
- Carcinogens
- Lipid Bilayers
- Receptors for Activated C Kinase
- Receptors, Cell Surface
- Spin Labels
- Protein Kinase C
- Tetradecanoylphorbol Acetate
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Topics |
- Animals
- Binding Sites
- Brain
(metabolism)
- Carcinogens
(metabolism)
- Cell Membrane
(metabolism)
- Electron Spin Resonance Spectroscopy
(methods)
- Kinetics
- Lipid Bilayers
- Mathematics
- Mice
- Models, Theoretical
- Protein Kinase C
(metabolism)
- Receptors for Activated C Kinase
- Receptors, Cell Surface
(metabolism)
- Spin Labels
- Tetradecanoylphorbol Acetate
(analogs & derivatives, metabolism)
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