Phosphatidylinositol Cycle Metabolites in Samanea saman Pulvini

The major metabolites of the phosphatidylinositol cycle from extracts of [(32)PO(4)]- and [(3)H]-inositol-labeled Samanea saman pulvini were separated. The membrane localized phosphoinositides were separated by thin layer chromatography, identified by comparison with purified lipid standards, and quantitated based on incorporation of radiolabel. The ratio of radioactivity in phosphatidylinositol:phosphatidylinositol 4-phosphate:phosphatidylinositol 4,5-bisphosphate is about 32:8:1. The aqueous inositol phosphates were separated by anion exchange chromatography using conventional liquid chromatography and by high performance liquid chromatography (HPLC) and were identified by comparison with standards. Analysis by HPLC reveals that (32)P-labeled pulvini have inositol 1-phosphate, inositol 1,4-bisphosphate, and inositol 1,4,5-trisphosphate that co-migrate with red blood cell inositol phosphates, but (3)H-inositol-labeled pulvini appear to have a variant profile.