Diprotin B is primarily used in biochemical research as a selective inhibitor of dipeptidyl peptidase IV (DPP-IV). This enzyme plays a significant role in the regulation of various physiological processes, including glucose metabolism, by degrading incretin hormones like GLP-1. By inhibiting DPP-IV, Diprotin B prevents the breakdown of GLP-1, which enhances insulin secretion and helps in studying the mechanisms of blood sugar regulation and potential treatment pathways for diabetes. Additionally, it is utilized in the development of enzyme inhibitors for therapeutic applications, particularly in the management of type 2 diabetes. Its role in enzyme inhibition also extends to research in immunology and cancer, where DPP-IV activity is a subject of interest.