D-Leucylglycylglycine is primarily utilized in biochemical research as a substrate for studying enzyme activity, particularly peptidases and proteases. It serves as a model peptide to investigate the specificity and mechanism of these enzymes in breaking down peptide bonds. Additionally, it is used in the development of peptide-based drugs and therapeutic agents, where its structure helps in understanding peptide stability and interactions. In cell culture studies, it can be employed to examine peptide transport and metabolism in various biological systems. Its role in these applications aids in advancing knowledge in enzymology, drug design, and cellular biology.