Used in glycopeptide synthesis as a protected glycosylated amino acid building block. The acetyl groups stabilize the sugar moiety during coupling reactions, while the fluorenylmethoxycarbonyl (Fmoc) group allows for orthogonal protection of the amino terminus in solid-phase peptide synthesis. Enables the preparation of complex glycopeptides containing lactose-linked serine for studies in glycobiology, vaccine development, and enzyme substrates. The compound is particularly useful for introducing beta-linked lactosyl units into peptides under mild, base-labile deprotection conditions.