Fmoc-Sar-Sar-OH is a peptide building block used in solid-phase peptide synthesis. It features an Fmoc (Fluorenylmethyloxycarbonyl) protective group on the N-terminus, which shields the amino group during peptide assembly. The core structure includes two Sar (Sarcosine) residues, a small, non-polar amino acid with a methyl group replacing one hydrogen, contributing to the peptide's flexibility and hydrophobic interactions. The -OH at the C-terminus indicates a free carboxyl group, allowing for further coupling with other amino acids. This compound is utilized to introduce specific dipeptide sequences into larger peptides, influencing their structure and function.