Global transcriptional regulator that complexes with cAMP and binds to specific DNA promoter sites, causing DNA-bending, to regulate transcription. cAMP improves binding to specific DNA sequences, probably by altering protein conformation. Involved in the regulation of gntP and gntK genes, which are involved in gluconate metabolism (PubMed:16385030). May form dimers which bind to the aceB promoter region in the presence of cAMP and repress the glyoxylate bypass genes (PubMed:15150232). It could be a positive regulator of rpf2 gene expression during growth on acetate as the sole carbon source, however because the cytosolic cAMP level is elevated in the presence of glucose and low upon growth on acetate, it is conceivable that it is unable to function as an activator under acetate conditions (PubMed:18355281). Homodimer. Seems to repress its own expression.