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Catabolite repression of various Bacillus subtilis catabolic operons which carry a cis‐acting catabolite‐responsive element (ORE), such as the gnt operon, is mediated by CcpA, a protein belonging to the GalR‐Lacl family of bacterial transcriptional repressors/activators, and the seryl‐phosphorylated form of HPr, a phosphocarrier protein of the phosphoenol‐pyruvate:sugar phosphotransferase system. Footprinting experiments revealed that the purified CcpA protein interacted with P‐ser‐HPr to cause specific protection of the gnt CRE against DNase I digestion. The specific recognition of the gnt CRE was confirmed by the results of footprinting experiments using mutant gnt CREs carrying one of the following base substitutions within the CRE consensus sequence: G to T at position +149 or C to Tat position +154 (+1 is the gnt transcription initiation nucleotide). The two mutant CREs causing a partial relief from …