The Mal regulon are set of genes excited by catabolite activator protein commonly known as CAP. The genes code for maltose metabolizing enzymes. The genes encoding the enzymes are non-contiguous, and regulated by multiple promoters. Mal regulon is regulated by catabolite activator protein in a novel manner. The Mal promoters are regulated by a protein called MalT that requires ATP and maltotriose to function. Maltotriose is a maltose regulon inducer. MalEp and malKp are examples of mal promoters that depends on both CAP and MalT to function while pulAp, pulCp and malPp are examples of mal promoters that depends on MalT only and malTp is controlled only be CAP.
References
Mal regulon Wikipedia(Text) CC BY-SA