The intense ongoing proteolytic activity is further supported by the increased expression of other proteases, such as dipeptidyl peptidase 4 (DPP4), aminopeptidase N (ANPEP), carboxypeptidase Q (CPQ), and hydrolases (N-sulphoglucosamine sulphohydrolase), in the grafts of patients developing AKI. The gene discussed is DPP4; the disease is acute kidney injury.