Review Question - QID 214591

A scientist is studying the molecular mechanisms underlying a rare genetic disorder that is caused by a single mutation. The scientist purifies the protein affected by this mutation and conducts an in vitro experiment to determine its function. She begins by adding either the wildtype or the mutated protein along with all necessary cofactors to a mixture of ribonucleic acid (RNA) strands that were produced through transcription. She finds that after allowing the mixture to react, the strands of RNA are significantly shorter in the wildtype but not the mutated condition. In addition, northern blot reveals smaller pieces of floating RNA in the wildtype but not the mutated conditions. A protein in which of the following classes is most likely being studied in this case?