At which ph levels did catalase cease to function?

a  pH level lower or higher than the optimum level between pH 7 and pH 11 

Catalase is an enzyme that speeds up chemical reactions in the human body. It breaks down hydrogen peroxide in the liver, but can also damage DNA. Catalase prevents damage by accelerating the breakdown of hydrogen peroxide into oxygen and water creating bubbles.

The optimum pH level of catalase is between pH 7 and pH 11, a  pH level lower or higher than this the catalase ceases to function.

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it