Phenylglyoxal Monohydrate is widely used in biochemical research as a selective reagent for modifying arginine residues in proteins and peptides. It is particularly valuable in studies involving protein structure and function, as it helps in identifying and analyzing arginine's role in enzymatic activity and protein interactions. Additionally, it is employed in the synthesis of heterocyclic compounds, which are important in pharmaceutical development. Its ability to act as a crosslinking agent also makes it useful in the preparation of modified biomaterials for various biomedical applications.