The MerR/NmlR family transcription factor of Streptococcus pneumoniae responds to carbonyl stress and modulates hydrogen peroxide production.

The NmlR(sp) transcription factor of Streptococcus pneumoniae is shown to induce adhC (alcohol dehydrogenase) expression in the presence of both formaldehyde and methylglyoxal. nmlR(sp) and adhC mutant strains display altered and opposite aerobic growth phenotypes. The nmlR(sp) strain exhibits increased resistance to high oxygen tension, attributable to decreased H(2)O(2) production, which correlated with downregulation of carbamoyl phosphate synthase (carB). This indicates a possible role for AdhC in aldehyde metabolism and a broader role for NmlR(sp) in the regulation of carbon metabolism.