G. Jacob et al., CHARACTERISTICS OF PHOSPHOLIPASE-C PRESENT IN MEMBRANES OF XENOPUS-LAEVIS OOCYTES - STIMULATION BY PHOSPHATIDIC-ACID, Comparative biochemistry and physiology. B. Comparative biochemistry, 106(4), 1993, pp. 895-900
1. Phospholipase C activity present in the membranes of Xenopus laevis
oocytes has been studied. 2. These membranes contain an activity capa
ble of hydrolyzing phosphatidylinositol, phosphatidylinositol 4-phosph
ate 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 polylysin
e cause significant stimulation of the phospholipase C activity. 5. Ph
osphatidic acid causes approximately a 2-fold stimulation of the hydro
lysis of both PtdIns and PtdIns 4,5-P2. With PtdIns as substrate, this
stimulatory effect of phosphatidic acid is specific and reaches a max
imum at a 400 muM concentration.