Phosphatidylinositol-specific phospholipase C from bovine blood platelets. Inhibition by calmodulin-inhibitors--activation by ATP and ADP.
The phospholipase C-activity in crude extracts of bovine blood platelets is strongly inhibited by the calmodulin-inhibitors fluphenazine and calmidazolium in the mM range, and activated by ATP and ADP, but not by AMP. The activating effect is also shown by the nonhydrolysable ATP- and ADP-analogs alpha,beta- and beta,gamma-methyleneadenosine 5'-triphosphate and alpha,beta-methyleneadenosine 5'-diphosphate, thus indicating that it is an allosteric effect. The stimulation of the phospholipase C-activity by ATP is also detectable in some partially purified fractions of the crude platelet extract, but it is abolished on further purification of the enzyme.
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002417:Cattle; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D010716:Phosphatidylinositols / Q000378:metabolism*; D010740:Phospholipases / Q000097:blood*; D010738:Type C Phospholipases / Q000097:blood*
D002147:Calmodulin; D010716:Phosphatidylinositols; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010740:Phospholipases; D010738:Type C Phospholipases