5-biphosphate,phosphatidylinositol 4 meaning

[Medicine]
A phosphoinositide present in all eukaryotic cells,particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C,with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol,and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew,The Encyclopedia of Molecular Biology,1994)