Phosphatidic Acid (PA) is a critical precursor for the biosynthesis of many lipids in the cell and plays a critical role in membrane structure and acts as a signaling lipid, recruiting cytosolic proteins to the cell membrane. Cell Biolabs’ Total Phosphatidic Acid Assay Kit is a simple, fluorometric assay that quantitatively measures total phosphatidic acid content, including lysophosphatidic acid (LPA), in samples by a coupled enzymatic reaction system. First, lipase is used to hydrolyze phosphatidic acid in samples to glycerol-3-phosphate. Next, the glycerol-3-phosphate product is oxidized by glycerol-3-phosphate oxidase (GPO), producing hydrogen peroxide which reacts with the kit’s fluorometric probe and detected by fluorescence plate reader. The kit has a detection sensitivity limit of 5 µM. Each kit provides sufficient reagents to perform up to 100 assays, including blanks, standards and unknown samples.