Method to Detect PDE Inhibitor Binding

Phosphodiesterase-5 (PDE5) is an enzyme which degrades cyclic guanosine monophosphate (cGMP) in smooth muscle cells. The common known drug Viagra is similar in molecular structure to cGMP and acts as a competitive binding agent of PDE5. Thus in the presence of Viagra unbound cGMP levels increase which results in smooth muscle relaxation or vasodilation leading to an increased inflow of blood. Vanderbilt researchers have developed a method for assaying compounds which bind PDEs. Not only will this method be useful in identify other PDE inhibitors but due to the high affinity of this system this method could be used to identify and isolate PDEs from various crude tissue fractions.

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U.S. Patent 7,217,527: Assay for phosphodiesterase function