Not exactly, but under the proper circumstances, enzyme activity can be affected - all depends on the conditions prior to, and after freezing. My graduate degree was studying reproductive enzyme activity, and examining the results using transmission electron microscopy. We regularly stored all biological materials in frozen form. When thawed, they were as active as the day they were frozen. However, the prepared materials must be frozen as quickly as possible because any protease activity at room temperature will continue to digest proteins, even the enzymes themselves, which are also protein in nature.