A simple assay for the quantitative evaluation of Phospholipase D activity

We describe the preparation of phosphatidyl p-nitrophenol (PpNP) and its use as a substrate in an assay for the quantitative evaluation of Phospholipase D. The solution of the substrate in Tris HCl buffer, pH 8, and Triton X is mixed directly with an aliquot of fermentation broth and the absorbance of the solution read at 405 nm. The method is rapid, sensitive and inexpensive.