Protein Disulfide Isomerase (PDI) from bovine liver is widely used in biochemical research and pharmaceutical applications due to its role in catalyzing the formation, reduction, and isomerization of disulfide bonds in proteins. It is essential in studying protein folding mechanisms, ensuring proper tertiary and quaternary structures of proteins. In biotechnology, PDI is employed to enhance the production of recombinant proteins, particularly those requiring correct disulfide bond formation for functionality. It is also utilized in the development of therapeutic proteins and antibodies, where proper folding is critical for efficacy. Additionally, PDI is used in diagnostic assays to investigate diseases related to protein misfolding, such as neurodegenerative disorders. Its application extends to industrial processes, including the production of enzymes and other bioactive proteins, where it improves yield and stability.