Phosphatidylserine Assay Kit (Fluorometric)

Phosphatidylserine (PS) is a glycerophospholipid consisting of a phosphatidyl group attached to L-serine via a phosphodiester linkage. PS is a critical component of the cellular plasma membrane and accounts for 2-15% of plasma membrane lipid composition, depending on the cell or tissue type. The highest concentrations of PS are found in neuronal tissues, which are critical for maintaining conduction velocity in myelinated neurons, as well as for higher order cognitive skills such as learning and memory. In normal, healthy cells, PS is held in the inner membrane surface (facing the cytosol) by the lipid transporter protein flippase. However, in apoptotic cells, PS molecules ‘shuffle′ between the inner and outer plasma membrane monolayers. When PS molecules flip to the extracellular (outer) surface of the cell membrane, they act as a signal for macrophages to engulf and digest the (apoptotic) cell.

Compatible with high-throughput handling systems.

Suitable for the measurement of phosphatidylserine concentration in lipid extracts such as soft tissue homogenates (i.e. liver, brain, etc.) and cultured cell lysates (adherent or suspension cells).

The Phosphatidylserine Assay Kit allows for quantification of PS in lipid extracts of cell and tissue lysates. The assay is based on the enzymatic cleavage of PS to yield phosphatidic acid and L-serine, which is subsequently metabolized and reacts with a probe to form a stable fluorophore at λex = 538 nm/λem = 587 nm. The assay is selective for PS (other phospholipids such as phosphatidylcholine, phosphatidylethanolamine or phosphatidic acid do not interfere). The kit is high-throughput ready and highly sensitive, detecting as little as 50 pmole/well of PS (5 μM in a 10 μL sample volume).