No, cAMP is not a protein kinase; it activates a protein kinase. Specifically, cAMP (cyclic adenosine monophosphate) activates cAMP-dependent protein kinase (PKA). According to the provided reference, PKA is a member of the protein kinase superfamily, and its catalytic subunit (C) is a structural prototype for the entire family. The inactive PKA holoenzyme consists of a regulatory (R) subunit dimer and two catalytic subunits. cAMP binds to the regulatory subunits, causing them to release the catalytic subunits, which then become active and can phosphorylate target proteins.
In simpler terms:
- cAMP: A signaling molecule.
- PKA: A protein kinase.
- The relationship: cAMP activates PKA.
| Feature | cAMP | PKA |
|---|---|---|
| Function | Second messenger/Signaling molecule | Protein kinase (enzyme that phosphorylates proteins) |
| Activation | Activated by various stimuli | Activated by cAMP |
| Role | Activates PKA | Phosphorylates target proteins |
| Chemical Nature | Cyclic nucleotide | Protein |
