Phosphatidylcholine (PC) is a phospholipid which incorporates choline as the headgroup of the lipid. PC is a major constituent of biological membranes and is involved in cell signaling through release of choline by phospholipase D leaving the second messenger phosphatidic acid. BioVision's Phosphatidylcholine Assay Kit is a simple convenient means of measuring Phosphatidylcholine in a variety of biological samples. The kit utilizes an enzyme-coupled assay in which PC is hydrolyzed, releasing choline which is subsequently oxidized resulting in development of the OxiRed probe to generate fluorescence (Ex/Em 535 nm 587 nm) and absorbance (570 nm). BioVision’s Phosphatidylcholine kit measures PC in the range of 0.1 to 10 nmol per sample. PC is present in serum at ~ 0.2-2.5 mM (~50-200 mg/dL).