Diamine oxidase from porcine kidney is primarily used in biochemical research to study histamine metabolism and its role in allergic reactions and inflammation. It is employed in enzymatic assays to measure histamine levels in biological samples, aiding in the diagnosis of conditions like histamine intolerance. Additionally, it serves as a tool in food science to monitor histamine content in products such as fish and fermented foods, ensuring safety and quality. The enzyme is also utilized in pharmaceutical studies to develop treatments targeting histamine-related disorders.