Enzymes at the wrong pH experience changes in the charge of the molecule, this can cause impacts on hydrogen and iconic bonds. Enzymes become denatured as terry structure is lost and the active site is no longer specific to the substrate.Temperature increases the kinetic energy between enzyme and substrate allowing for more random collisions which in turn allows for more enzyme-substate complexes to be formed. When away from the optimum hydrogen and ionic bonds bonds break due to the increase kinetic energy of the molecule causing loss of tertiary structure which means the active site is no longer complimentary to the substrate.