Z-Ile-Leu-aldehyde is primarily used in biochemical research as a protease inhibitor. It effectively blocks the activity of proteolytic enzymes, making it valuable in studying enzyme mechanisms and protein degradation pathways. This compound is also utilized in peptide synthesis, where it serves as a building block or intermediate for creating more complex peptide structures. Additionally, it finds application in drug discovery, particularly in the development of inhibitors targeting specific proteases involved in diseases. Its role in modulating enzyme activity makes it a useful tool in both academic and industrial research settings.