Enhancement of Platelet and Muscle Actomyosin ATPase Activity and Superprecipitation by the Tumour-promoter 12-O-Tetradecanoyl-phorbol-13-acetate (PMA)

THE 12-O-tetradecanoate 13-acetate ester of the 20-carbon alcohol phorbol (phorbol myristate acetate, or PMA) is the most active irritant and tumour-promoting ingredient of croton oil1,2. It enhances the activity of some membrane-bound enzymes, especially Na+-K+-dependent ATPase3.