Enzymes show optimum activity between 37 C to 50 C however works:

above 50 C

Below #7 C

It loses activity permanently above 50 C

it loses activity permanently below 37 C

Explanation

If the temperature increases from 37 degrees Celsius to 50 degrees Celsius, the enzyme activity will decrease.

enzymes are proteins, they are denatured by heat.

Therefore, at higher temperatures (over about 55°C in the graph below) there is a rapid loss of activity as the protein suffers irreversible denaturation.