Cyclic amp receptor protein
a transcriptional regulator in prokaryotes which, when activated by binding cyclic amp, acts at several promoters. Cyclic amp receptor protein was originally identified as a catabolite gene activator protein. It was subsequently shown to regulate several functions unrelated to catabolism, and to be both a negative and a positive regulator of transcription. Cell surface cyclic amp receptors are not included (cyclic amp receptors), nor are the eukaryotic cytoplasmic cyclic amp receptor proteins, which are the regulatory subunits of cyclic amp-dependent protein kinases.