Characteristics of phospholipase C present in membranes of Xenopus laevis oocytes. Stimulation by phosphatidic acid.
1. Phospholipase C activity present in the membranes of Xenopus laevis oocytes has been studied. 2. These membranes contain an activity capable of hydrolyzing phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. 3. Hydrolysis of PtdIns 4,5-P2 is absolutely dependent on the presence of Ca2+, however, the hydrolysis of PtdIns occurs in the absence of Ca2+ but addition of the cation stimulates the reaction. 4. Spermine, spermidine and polylysine cause significant stimulation of the phospholipase C activity. 5. Phosphatidic acid causes approximately a 2-fold stimulation of the hydrolysis of both PtdIns and PtdIns 4,5-P2. With PtdIns as substrate, this stimulatory effect of phosphatidic acid is specific and reaches a maximum at a 400 microM concentration.
Jacob
G
G
Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago.
Allende
C C
CC
Allende
J E
JE
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006868:Hydrolysis; D009865:Oocytes / Q000187:drug effects / Q000201:enzymology*; D010712:Phosphatidic Acids / Q000494:pharmacology*; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010743:Phospholipids / Q000494:pharmacology; D011107:Polylysine / Q000494:pharmacology; D013095:Spermidine / Q000494:pharmacology; D013096:Spermine / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*; D014982:Xenopus laevis
D010712:Phosphatidic Acids; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D010743:Phospholipids; C037178:phosphatidylinositol 4-phosphate; D011107:Polylysine; D013096:Spermine; D010738:Type C Phospholipases; D002118:Calcium; D013095:Spermidine