How does enzyme denaturation affect enzyme activity?

Enzyme denaturation results in loss of enzyme activity. 

Enzymes have very specific structures that enable them to perform their functions. Changes in temperature, pH or salt concentration may disrupt the bonds and interactions that hold the enzyme together and give it its specific structure. This disruption of the bonds causes the enzyme to denature, wherein it unfolds and loses its three-dimensional native conformation. When the enzyme denatures and loses its shape, it loses its ability to selectively bind to substrates, resulting in a loss of function.