A high-throughput assay for cyclic nucleotide phosphodiesterases

Area of Science:

• Biochemistry
• Enzymology
• Drug Discovery

Background:

• Screening for cyclic nucleotide phosphodiesterase (PDE) inhibitors is crucial for drug discovery.
• Current assay throughput limits the exploration of large chemical and natural product libraries.

Purpose of the Study:

• To develop a sensitive, high-throughput assay for monitoring phosphodiesterase activities.
• To enable efficient identification of selective cyclic nucleotide phosphodiesterase inhibitors.

Main Methods:

• A novel phosphodiesterase assay was developed utilizing selective precipitation of radiolabeled 5'-nucleotide products (GMP or AMP) by zinc and barium.
• The assay was adapted to a microtiter plate format, achieving over 960 assays per day.
• Enzyme kinetics and inhibitor IC50 values were determined for selected phosphodiesterases.

Main Results:

• The assay accurately measures phosphodiesterase product formation.
• Accurate enzyme kinetic constants were determined for three different phosphodiesterases, aligning with literature values.
• IC50 values for known inhibitors were successfully determined, validating the assay's efficacy.

Conclusions:

• The developed assay is sensitive and suitable for high-throughput screening of phosphodiesterase inhibitors.
• This method provides a robust platform for identifying selective PDE inhibitors.
• The assay facilitates accurate determination of enzyme kinetics and inhibitor potencies.