Identification of a pH 6.5 acetohydroxyacid synthetase inBacillus subtilis
Acetohydroxyacid synthetase activity of crude extracts ofBacillus subtilis grown in pH 7.0 minimal medium has a pH optimum of 7.5. However, the activity of extracts of cells grown in minimal medium of pH 6.0 shows a pH optimum of 6.5. Acetate or propionate induces formation of the pH 6.5 activity. Hydroxyapatite chromatography of a crude extract of cells grown in pH 7.0 medium shows one major and one minor peak of enzymatic activity. Both peaks have a pH optimum of 7.5–8.0. However, chromatography of an extract of cells grown in the presence of acetate reveals three peaks of activity: one major peak with a pH optimum of 6.5 and two minor peaks both having a pH optimum of 7.5–8.0.
Key wordsAcetohydroxy Acid Synthetase (pH 6.5) Bacillus subtilis Isoenzymes Catabolic and Anabolic Isoenzymes
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