Catalase activity in crude extracts of Escherichia coli has two pH optima: one at pH 6.8 and the other at pH 10.5. The former is inducible by H2O2 and is the major species in exponential cells. The latter is constitutive and is the major species in stationary cells. Both activities are repressed by glucose. Catalase-negative mutants that are impaired in the pH-6.8 activity were isolated by the inability of aerobically grown mutagenized colonies to decompose H2O2. One mutant (cat2) characterized is hypersensitive to H2O2.
|Number of pages||5|
|State||Published - Jan 1984|