Phosphodiesterase

Phosphodiesterase (PDE) is a type of enzyme that plays a crucial role in cellular processes. It is responsible for breaking down phosphodiester bonds, which are common in many biological molecules such as DNA and RNA.

Function

Phosphodiesterases function by hydrolyzing phosphodiester bonds in cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are second messengers in a variety of cells. This hydrolysis process results in the deactivation of the cyclic nucleotides, thus regulating the cells' responses to hormones and other signaling molecules.

Types

There are 11 families of phosphodiesterases, each with different substrate specificities, regulatory properties, and tissue distributions. These include PDE1 - PDE11. Each type has a unique role in the body, and their dysfunction can lead to a variety of diseases.

Clinical significance

Phosphodiesterase inhibitors, such as sildenafil (Viagra), are drugs that block one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by the respective PDE subtype(s). The ubiquity of the enzyme type means that non-specific inhibitors have a wide range of actions, the actions in the heart, and lungs being some of the first to be identified.

See also

• Phosphodiesterase inhibitor
• Cyclic nucleotide phosphodiesterases
• Phosphodiesterase 5
• Phosphodiesterase 4

References

• 
  Cyclic guanosine monophosphate (cGMP) structure
• 
  Cyclic adenosine monophosphate (cAMP) structure
• 
  Phosphodiesterase families