Explain the effect of an increase in temperature on enzymatic activity

All enzymes have an optimum temperature, at which rate of reaction/catalysis is fastest. Any deviation from the optimum temperature will slow down rate of reaction.

Like most chemical reactions, an increase in temperature will increase the rate of reaction. However, enzymes are proteins and have the ability to be denatured above a certain temperature. At this point, the enzyme loses its catalytic properties and rate of reaction will decrease rapidly.

The relationship between temperature change and rate of enzyme activity is best demonstrated with this graph; commonly reffered to as 'the bell curve'.