In a range of 0-35oC, the rate of reaction of an enzyme is proportional to temperature. Above 35oC and below 0oC enzyme activity slows down and eventually stops. Explain why?
Temperature increases will speed up the rate of enzyme-catalyzed reactions, but only to a certain limit.
Optimum Temperature:
Every enzyme works at its maximum rate at a specific temperature called the optimum temperature for that enzyme. When the temperature rises to a certain limit, the heat adds in the activation energy and also provides kinetic energy and so reactions are accelerated.
Denaturation of Enzyme:
When the temperature is raised well above the optimum temperature, the heat energy increases the vibrations of atoms of enzyme molecules and the globular structure of the enzyme is lost. This is known as the denaturation of the enzyme. It results in a rapid decrease in the rate of enzyme action and it may be blocked completely.
Conclusion: Thus above 35°C and below 0°C Enzyme activity slows down and eventually stops.