Used in peptide synthesis as a protected amino acid building block, particularly in the preparation of collagen-like peptides and enzyme substrates. The tosyl (Tos) group acts as a protecting group for the amine function of glycine, allowing selective coupling at the carboxyl end in stepwise solid-phase or solution-phase peptide synthesis. Commonly employed in the development of protease inhibitors and bioactive peptides where a proline residue is required at the C-terminus. Also utilized in the synthesis of model compounds for studying peptide conformation and enzyme specificity, especially for enzymes recognizing proline-rich sequences.