title: Purification of a phosphoinositide-specific phospholipase C from bovine brain.
abstract: A soluble phosphoinositide-specific phospholipase C (PLC) was purified 58,000-fold from bovine brain. The enzyme, one of six distinct PLC activities detected in brain, accounted for approximately 15% of the soluble phosphatidylinositol-4,5-bisphosphate-phospholipase C (PIP2-PLC) activity in this tissue. The purification scheme included hydrophobic chromatography on phenyl-Sepharose and affinity chromatography on phosphatidylinositol-Sepharose (PI-Sepharose). The enzyme was specifically eluted from the PI-Sepharose with PI, calcium, and detergent. The purified PLC had an estimated molecular weight of 88,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and behaved as a monomeric protein during sedimentation on glycerol gradients. The enzyme required calcium for activity, exhibited a pH optimum of 6.5, and cleaved only phosphoinositides. The rates of PIP2 and phosphatidyl-4-monophosphate hydrolysis exceeded the rate of PI hydrolysis under all conditions tested. These properties are consistent with a potential role for this PLC in the early events involved in cellular calcium mobilization.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002846:Chromatography, Affinity; D002847:Chromatography, Agarose; D006863:Hydrogen-Ion Concentration; D010716:Phosphatidylinositols / Q000378:metabolism*; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000302:isolation & purification*
chemical_list: D010716:Phosphatidylinositols; D010738:Type C Phospholipases; D002118:Calcium