Activity and stability of catalase in blood and tissues of normal and acatalasemic mice

Catalase activity in blood, liver, and kidney of a mutant strain Cs^b has been found to be decreased as compared to the level in normal mice. However, the extent of the reduction largely depends on the conditions used for activity determination, in particular, temperature and duration of the incubation period. In liver, this effect is most pronounced, the observed activity in mutants varying between 21 and 85% of the normal level. This dependence on the assay conditions is mainly due to the unusual heat lability of the variant enzyme, which undergoes rapid inactivation when incubated at 37 C.