What are the names of all enzymes that can serve as inhibitors?
SELECT distinct ( T1.name )  FROM enzyme AS T1 JOIN medicine_enzyme_interaction AS T2 ON T1.id   =   T2.enzyme_id JOIN medicine AS T3 ON T2.medicine_id   =   T3.id WHERE T2.interaction_type   =   'inhibitor'
enzymes that can serve as inhibitors refers to joining enzyme table with medicine_enzyme_interaction on enzyme_id and filtering where interaction_type = 'inhibitor'; distinct names of these enzymes are required.