Crude extracts of wild-type Escherichia coli contain two catalase species that separate on native polyacrylamide gels. The slow-migrating enzyme (HPII) has two pH optima of activity (at pH 6.8 and 10.5), is activated at 70°C, is sensitive to inhibitory by 3-amino-1,2,4-triazole and has Km values of 18.2 m M at pH 6.8 and of 10 m M at pH 10.5. The fast-migrating enzyme has a single pH optimum of 6.8 and is composed of two isozymes (HPI-A and HPI-B). Its activity is labile at 70°C, it is relatively resistant to inhibition by 3-amino-1,2,4-triazole and has a Km value of 3.7 m M.
|Number of pages||5|
|State||Published - Nov 1985|