An improved assay for the determination of phospholipase C activity

Abstract Phospholipases C (PLC, EC 3.1.4.3) are enzymes that specifically hydrolyze the C‐O‐P bond in phospholipids, yielding sn ‐1,2(2,3)‐diacylglycerides and the phosphate residue bearing the corresponding headgroup. The biochemical characterization of PLC requires methods for the reliable determination of their activity. Here, an assay is described in which the phosphate residue released by the PLC is cleaved with an alkaline phosphatase. The phosphate formed is then extracted with n ‐butanol and quantified as phosphomolybate complex. The applicability of this method is demonstrated for a concentration range from 10 nM to 10 mM for a range of phospholipids bearing different headgroups in an aqueous and a two‐phase system. The method has the additional advantage that the crude enzyme can be used without the need for purification.