PDE5A1 Assay Kit

Phosphodiesterases (PDEs) play an important role in dynamic regulation of cAMP and cGMP signaling. PDE5A1, also known as cGMP-inhibited phosphodiesterase, has been implicated in cardiovascular function and fertility. The PDE5A1 Assay Kit is designed for identification of PDE5A1 inhibitors using fluorescence polarization. The assay is based on the binding of a fluorescent nucleotide monophosphate generated by PDE5A1 to the binding agent.

Phosphodiesterases catalyze the hydrolysis of the phosphodiester bond in dye-labeled cyclic monophosphates.  Beads selectively bind the phosphate group in the nucleotide product.  This increases the size of the nucleotide relative to unreacted cyclic monophosphate.  In the polarization assay, dye molecules with absorption transition vectors parallel to the linearly-polarized excitation light are selectively excited.  Dyes attached to the rapidly-rotating cyclic monophosphates will obtain random orientations and emit light with low polarization.  Dyes attached to the slowly-rotating nucleotide-bead complexes will not have time to reorient and therefore will emit highly polarized light.