Glycine p-nitroanilide is primarily used as a substrate in enzymatic assays, particularly for the detection and measurement of enzyme activity. It is commonly employed in biochemical research to study enzymes like proteases and peptidases, which cleave the compound to release p-nitroaniline. The release of p-nitroaniline, which is yellow in color, can be easily monitored spectrophotometrically, making it a useful tool for quantifying enzyme kinetics and activity. This application is valuable in both academic research and industrial settings for understanding enzyme mechanisms and optimizing enzymatic processes.