title: Soluble phorbol ester binding sites and phospholipid- and calcium-dependent protein kinase activity in cytosol of chick oviduct.
abstract: A large amount of specific high affinity binding sites for tumor promoting phorbol esters as well as of a Ca2+- and phospholipid-dependent protein kinase is present in cytosol of chick oviduct. 12-O-Tetradecanoyl-phorbol-13-acetate (TPA) is able to replace either Ca2+ or the phospholipid phosphatidylserine as activators of the kinase to some extent. The maximum activity of the enzyme in the presence of Ca2+ and phosphatidylserine, however, cannot be increased further by TPA. Various second stage tumor promoters also exhibit the capacity to stimulate the protein kinase, whereas the non-promoting phorbol ester 4-O-methyl-TPA, as well as the non-promoting, but with respect to other responses TPA-like, calcium ionophore A23187, do not affect the kinase.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology*; D002645:Chickens; D003600:Cytosol / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D010057:Oviducts / Q000378:metabolism*; D010704:Phorbols / Q000378:metabolism*; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*; D011494:Protein Kinases / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D010704:Phorbols; D010718:Phosphatidylserines; D010743:Phospholipids; D011494:Protein Kinases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium