CodY regulates extracellular nuclease activity. Sterile CSPs were prepared from the wild-type and codY mutant strains grown under the same conditions that were used to analyze exoproteins by 2-DE. CSPs from the wild-type strain (lanes 1, 3, 5) and codY mutant (lanes 2, 4, 6) were incubated with DNA substrate for 75 min. (lanes 1,2); 90 min. (lanes 3,4); and 18 h (lanes 5, 6). As a control, sterile CDM broth was similarly incubated for 18 h with the DNA substrate (lane 7).