Actinoplanessp. SE50/110 is the industrially relevant producer of acarbose, which is used in the treatment of diabetes mellitus. Recent studies elucidated the expression dynamics inActinoplanessp. SE50/110 during growth. From these data, we obtained a large genomic region (ACSP50_3900toACSP50_3950) containing 51 genes, of which 39 are transcribed in the same manner. These co-regulated genes were found to be stronger transcribed on maltose compared with glucose as a carbon source. The transcriptional regulator MalT was identified as an activator of this maltose-regulated large genomic region (MRLGR). Since most of the genes are poorly annotated, the function of this region is farther unclear. However, comprehensive BLAST analyses indicate similarities to enzymes involved in amino acid metabolism. We determined a conserved binding motif of MalT overlapping the -35 promoter region of 17 transcription start sites inside the MRLGR. The corresponding sequence motif 5 '-TCATCC-5nt-GGATGA-3 ' displays high similarities to reported MalT binding sites inEscherichia coliandKlebsiella pneumoniae, in which MalT is the activator ofmalgenes. AmalTdeletion and an overexpression mutant were constructed. Differential transcriptome analyses revealed an activating effect of MalT on 40 of the 51 genes. Surprisingly, no gene of the maltose metabolism is affected. In contrast to many other bacteria, MalT is not the activator ofmalgenes inActinoplanessp. SE50/110. Finally, the MRLGR was found partly in other closely related bacteria of the family Micromonosporaceae. Even the conserved MalT binding site was found upstream of several genes inside of the corresponding regions.