Fmoc-NMe-PEG4-C2-acid（Cat No.:I015979）is a functionalized polyethylene glycol linker incorporating a four-unit PEG chain, a two-carbon (C2) spacer, and a terminal carboxylic acid group. It also features an N-methylated amine protected by an Fmoc group, enabling orthogonal deprotection strategies in solid-phase synthesis. The PEG4 backbone enhances solubility, flexibility, and reduces steric hindrance, while the C2 spacer provides additional structural adaptability. This versatile reagent is widely employed in peptide synthesis, drug design, and bioconjugation, facilitating linker construction, protein modification, and development of multifunctional biomolecules or advanced therapeutic platforms.