Formation of phosphatidylinositol 3-phosphate by isomerization from phosphatidylinositol 4-phosphate.
We have synthesized phosphatidylinositol 3-phosphate from phosphatidylinositol 4-phosphate by using diisopropylcarbodiimide to promote migration of the 4-phosphate via a cyclic phosphodiester intermediate. The product was isolated by a thin-layer chromatographic method that depends on the ability of phosphatidylinositol 4-phosphate, but not phosphatidylinositol 3-phosphate, to form complexes with boric acid. The final yield of the procedure was 8% phosphatidylinositol 3-phosphate, which was approximately 80% pure. The product was shown to be phosphatidylinositol 3-phosphate by the following criteria: (i) cochromatography with an authentic standard on borate thin-layer chromatography, (ii) cochromatography of the deacylated product with glycerophosphoinositol 3-phosphate on high-performance liquid chromatography, (iii) conversion of the product to phosphatidylinositol by homogeneous phosphatidylinositol 3-phosphate 3-phosphatase, and (iv) deacylation and deglyceration of the product to a compound that comigrates with inositol 1,3-bisphosphate on high-performance liquid chromatography. The availability of mass amounts of phosphatidylinositol 3-phosphate will allow further elaboration of reactions in this recently discovered pathway of phosphatidylinositol metabolism.
Walsh
J P
JP
Washington University School of Medicine, Division of Hematology-Oncology, St. Louis, MO 63110-1093.
Caldwell
K K
KK
Majerus
P W
PW
D001345:Autoradiography / Q000379:methods; D002855:Chromatography, Thin Layer; D007202:Indicators and Reagents; D007536:Isomerism; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000737:chemistry*; D010761:Phosphorus Radioisotopes
D007202:Indicators and Reagents; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; C055525:phosphatidylinositol 3-phosphate; C037178:phosphatidylinositol 4-phosphate