Effect of growth conditions on the synthesis of nitrate reductase components in chlorate resistant mutants of Escherichia coli K 12.

The chlorate resistant mutants of $\text{Escherichia coli}$ synthetize, in variable quantities, proteins which give immunocomplex with specific nitrate reductase antiserum. The biosynthesis of these cross reacting materials presents the same type of regulation as nitrate reductase of the wild type. C.R.M. biosynthesis is repressed by oxygen and even in the presence of nitrate, the oxygen inhibition is not reversed with chlorate mutants and wild type. With anaerobically grown cells, nitrate acts as an inducer and increases the amount of antibody-precipitable material, three times in mutants and even four times with Chl-E.