Incorporation of 32P from [γ-32P] ATP into Polyphosphoinositides and Phosphatidic Acid in Subcellular Particles of Guinea Pig Brain

Abstract

The subcellular particles of guinea-pig brain were incubated with γ⁻³²P] ATP in the presence of potassium chloride (100 mAf), magnesium sulfate (3mM) and Tris-HCl buffer (pH7.4). Labeling of phospholipids was followed by the column method after deacylation. The results are summerized as follows: 1) Labeling of triphosphoinositide, diphosphomositide and phosphatidic acid with ³²P was observed after a few second incubation at 0°C. In various periods of incubation up to a few minutes the percentage of ³²P-activity in polyphosphoinositides increased,whereas no increase was observed in phosphatidic acid. 2) The incorporation of ³²P-phosphate into phosphoinositides was markedly depressed by the addition of calcium ion in a final concentration of 3mM. 3) Sodium ion exerted no specific effect on the labeling of the phospholipids from [γ⁻³²P] ATP.