BDK (Bradykininase) is a serine protease involved in the kinin release system, responsible for generating bradykinin, a peptide with vasodilatory and hypotensive effects. BDK consists of multiple functional domains and is primarily located in endothelial cells and the kidneys. BDK plays a crucial role in regulating vasodilation, inflammatory responses, and water-electrolyte balance. The expression of BDK is tissue-specific, and mutations or dysregulation in its expression are associated with various diseases, including hypertension, cardiovascular diseases, and kidney disease. The activity of BDK is regulated by multiple factors, affecting the physiological and pathological processes of cells.