[38] Activity Stain for the Detection of Cyclic Nucleotide Phosphodiesterase in Polyacrylamide Gels

The localization of cyclic nueleotide phosphodiesterase activity in acrylamide gels is based upon methods developed for the detection of alkaline phosphatase activity. A similar method has been utilized to localize cyclic nucleotide phosphodiesterase histochemically. Standard polyacrylamide disc gel electrophoresis in 7.5% acrylamide gel is performed according to the method of Davis at pH 9.0. Electrophoresis can also be performed at pH 7.0 and in various concentrations of polyacrylamide gel. Approximately 0.003 unit of cyclic nucleotide phosphodiesterase in 200 μl of 20% sucrose is layered on the stacking gel, and a constant current of 1.5 mA/gel is applied until the tracking dye (bromophenol blue) is about 2 mm from the end of the gel.