1-phosphatidylinositol-4,5-bisphosphate phosphodiesterase beta 1 (EC 3.1.4.11) (Phosphoinositide phospholipase C) (Phospholipase C- beta-1) (PLC-beta-1) (PLC-I) (PLC-154); The production of the second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) is mediated by activated phosphatidylinositol-specific phospholipase C enzymes (1216 aa)