What would happen to an enzyme if the temperature and ph changed significantly beyond the enzymes optimum level

At low temperatures, enzyme reactions are slow. They speed up as the temperature rises until an optimum temperature is reached. After this point the reaction will slow down and eventually stop.

 enzyme activity increases steadily between 0 ºC and 40 ºC. It peaks at 40 ºC (the enzyme's optimum temperature) then decreases rapidly.

Different enzymes work best at different pH values, their optimum pH. Many enzymes work fastest in neutral conditions. Making the solution more acidic or alkaline will slow the reaction down. At extremes of pH the reaction will stop altogether.

Some enzymes, such as those used in digestion, are adapted to work faster in unusual pH conditions. For example, stomach enzymes have an optimum pH of 2, which is very acidic.

 enzyme activity increases between pH 4.5 and pH 8. It peaks at pH 8, then decreases.

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