Fmoc-D-Cit-OH is widely used in peptide synthesis as a building block. It is particularly valuable in solid-phase peptide synthesis (SPPS) due to the Fmoc protecting group, which can be easily removed under mild basic conditions. This compound is essential for incorporating D-citrulline into peptide sequences, enabling the study of peptide structure and function. It is also utilized in the development of peptidomimetics and bioactive peptides, contributing to research in drug discovery and biochemical studies. Additionally, Fmoc-D-Cit-OH plays a role in creating modified peptides for applications in immunology, such as the study of autoimmune diseases where citrullinated peptides are of interest.