Fluorescence studies on the interaction of the tumor promoter phorbol myristate acetate and related compounds with rat liver plasma membranes.
The interaction of the potent tumor-promoting agent phorbol myristate acetate (PMA) with purified rat liver plasma membranes suspended in phosphate-buffered saline (PBS), pH 7.4, was studied by fluorescence spectrophotometry. Exposure of membranes to PMA caused up to 21% decrease of the native membrane emission, i.e. the fluorescence of both tryptophan and tyrosine, compared to non-treated membranes. The decrease in the membrane emission varied with both the PMA and the membrane concentration. Treatment of rat liver plasma membranes with biologically less active analogs of PMA, phorbolol myristate acetate (PHMA) and 4a alpha-phorbol didecanoate (4a alpha-PDD), resulted in a 5-10% decrease of the native membrane emission. These studies suggest that PMA causes alterations in membrane structure which are due, at least in part, to conformational changes in the membrane proteins.
D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism*; D005260:Female; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009708:Nucleotidases / Q000378:metabolism; D010703:Phorbol Esters / Q000494:pharmacology; D010704:Phorbols / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D051381:Rats; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism*
D010703:Phorbol Esters; D010704:Phorbols; D013385:Succinate Dehydrogenase; D009247:NADH, NADPH Oxidoreductases; D009708:Nucleotidases; D005952:Glucose-6-Phosphatase; D010727:Phosphoric Diester Hydrolases; D013755:Tetradecanoylphorbol Acetate