A molecule of AMP (adenosine monophosphate) in which the phosphate group is joined to both the 3 ‘ and the 5’ positions of the ribose, forming a cyclic (ring) strucUire. When cAMP binds to CAP, the complex is a positive regulator of procaryotic transcription.
A second messenger for catabolic hormone effects. The hormone binds to a membrane receptor which in turn stimulates adenyl cyclase which acts on ATP to produce cyclic AMP.