Effect of spermine on the translocation of Mg2+-dependent phosphatidate phosphohydrolase.

Adipose cytosol treated with spermine showed an aggregation of a cytosolic component which was isolated by centrifugation at 16,000 X g for 20 min. The resultant pellet contained 10% of protein, 40% of lipid and over 75-97% of Mg2+-dependent phosphatidate phosphohydrolase and CTP:phosphocholine cytidylyltransferase activities present in the original cytosol. The specific activities of these enzymes increased 4-fold by the spermine treatment. Characterization of lipids in this component indicated the presence of mainly phospholipids. These studies suggest that the interaction between spermine, the cytosolic component and microsomal membranes may be involved in the translocation of Mg2+-dependent phosphatidate phosphohydrolase.