cAMP decomposition into AMP is catalyzed by the enzyme phosphodiesterase.
In humans, cyclic AMP works by activating protein kinase A (PKA, also known as cAMP-dependent protein kinase). This is normally inactive as a tetrameric holoenzyme, consisting of 2 catalytic and 2 regulatory units (C2R2), with the regulatory units blocking the catalytic centers of the catalytic units. Cyclic AMP binds to specific locations on the regulatory units of the protein kinase, and causes dissociation between the regulatory and catalytic subunits, thus activating the catalytic units and enabling them to phosphorylate substrate proteins.
The active subunits catalyze the transfer of phosphate from ATP to specific serine or threonine residues of protein substrates. The phosphorylated proteins may act directly on the cell's ion channels, or may become activated or inhibited enzymes. Protein kinase A can also phosphorylate specific proteins that bind to promoter regions of DNA, causing increased expression of specific genes. Not all protein kinases respond to cAMP: several types of protein kinases are not cAMP dependent, for example protein kinase C.
Further effects depend on cAMP-dependent protein kinase, which vary based on the type of cell.
An example of cAMP's function is the positive regulation of the lac operon. In an environment of a low glucose concentration, cAMP accumulates and binds to the allosteric site on CRP (cAMP receptor protein), a transcription activator protein. The protein assumes its active shape and binds to a specific site beside the lac promoter, making it easier for RNA polymerase to bind to the adjacent promoter to start transcription of the lac operon, increasing the rate of lac operon transcription. With a high glucose concentration, the cAMP concentration decreases, and the CRP disengages from the lac operon.
Study results from University of Texas Southwestern Medical Center in the area of adenosine monophosphate therapy published.
Mar 19, 2010; Scientists discuss in 'Environmental enrichment produces a behavioral phenotype mediated by low cyclic adenosine monophosphate...
Reports from University Hospital, German Cancer Research Center highlight recent research in adenosine monophosphate therapy.
Feb 23, 2010; Investigators publish new data in the report 'Distinct metabolism of cyclic adenosine monophosphate in regulatory and helper CD4+...
WIPO PUBLISHES PATENT OF NANJING UNIVERSITY OF TECHNOLOGY FOR "METHOD OF PREPARING CYCLIC ADENOSINE MONOPHOSPHATE" (CHINESE INVENTORS)
Dec 12, 2011; GENEVA, Dec. 12 -- Publication No. WO/2011/150724 was published on Dec. 08. Title of the invention: "METHOD OF PREPARING CYCLIC...