How does increasing temperature affect the rate of a reaction in the presence of an enzyme.

Initially increasing temperature will increase the rate of reaction. This is because the substrate molecules have greater kinetic energy so there are more frequent collisions with the enzyme/other molecules. However past a point the increasing temperature will alter the bonds in the tertiary structure of the enzyme causing it to change its shape resulting in less affinity for the substrate. Therefore there will be fewer enzyme-substrate complexes formed so a reduced rate of reaction. This can lead to the rate of reaction dropping to 0.