Abstract
Granules were isolated from sonicated rat mast cells on Percoll gradient and incubated with [γ32P] ATP in the presence of Mg2+ and exogenous diphosphoinositide. After stopping the reaction, lipid extraction of the intact membrane granules was performed with acidic medium and phospholipids were separated by thin layer chromatography on 1% (w/v) oxalic acid and potassium oxalate impregnated silica gel plates. Considerable amounts of radioactivity were found to be incorporated into TPI on both plates. Extensive washing of the granules did not significantly affect the 32P incorporation into TPI. The radioactivity in TPI was associated with the granule themselves and it is apparent that TPI is produced in rat mast cell granule.
