title: Cyclic 3':5'-nucleotide phosphodiesterase. Stimulation of bovine brain cytoplasmic enzyme by lysophosphatidylcholine.
abstract: Brain cytoplasmic cyclic 3':5'-nucleotide phosphodiesterase (EC 3.1.4.17) requires an endogenous Ca2+-binding protein for ful activity. We now show that lysophosphatidylcholine also effectively enhances activator-deficient phosphodiesterase activity. Stimulation by both ligands was immediate and reversible; both rendered the enzyme more thermally labile, decreased the energy of activation, and increased the Vmax of phosphodiesterase without affecting its apparent Km for adenosine 3'5'-monophosphate. However, the cofactor requirements of the two ligands were different. Although the protein activator gave a greater stimulation than lysophosphatidylcholine, the simultaneous presence of the two gave a stimulation comparable to lysophosphatidylcholine, suggesting that the effect of the latter was predominant. Phosphodiesterase was also stimulated by oleic acid, cardiolipin, and phosphatidylinositol, albeit to a less extent.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002118:Calcium; D002352:Carrier Proteins / Q000494:pharmacology; D002417:Cattle; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation; D007700:Kinetics; D008024:Ligands; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D010740:Phospholipases / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008024:Ligands; D008244:Lysophosphatidylcholines; D010740:Phospholipases; D010727:Phosphoric Diester Hydrolases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D002118:Calcium