Hippuryl-Arg (also known as hippuryl-L-arginine) is a synthetic dipeptide substrate commonly used in biochemical research to assay the activity of carboxypeptidase B (CPB) and other exopeptidases that cleave C-terminal basic amino acids like arginine. The enzyme hydrolyzes the bond between the hippuryl (benzoylglycyl) group and arginine, releasing hippuric acid, which can be quantified to study enzyme kinetics, specificity, and mechanisms in protein degradation and processing pathways. It is particularly valuable in investigations of proteolytic enzymes involved in physiological processes such as blood clotting and hormone regulation. Furthermore, Hippuryl-Arg is employed in clinical diagnostics to measure CPB activity in serum or tissue samples, aiding in the assessment of conditions like pancreatitis, liver disease, or other disorders associated with altered peptidase function. Its specificity contributes to advancements in enzymology, pharmacology, and medical diagnostics.