PROPERTIES AND SUBCELLULAR DISTRIBUTION OF PHOSPHATIDYLINOSITOL KINASE IN MAMMALIAN TISSUES

1. 1.Studies of subcellular fractions from rat liver indicate the presence of more than one phosphatidylinositol kinase. 2. 2.Some properties of two kinases in liver are reported. 3. 3.The distribution of phosphatidylinositol kinase in subcellular fractions from rat brain, kidney, heart, skeletal muscle and testis indicates that the enzyme is most active in fractions likely to contain the plasma membrane of these tissues. 4. 4.The enzyme is also present in human erythrocyte membranes and in the surface membrane fraction of rabbit polymorphonuclear leucocytes. 5. 5.Rat kidney, like rat liver, has a separate Cutscum-stimulated kinase associated with the endoplasmic reticulum. 6. 6.The kinase has been found in all tissues studied, but is most active in brain. 7. 7.A subcellular fractionation procedure for testis is presented and the purity of the fractions discussed. © 1969.