Deamination resin is used in solid-phase peptide synthesis to facilitate the selective removal of the Fmoc (fluorenylmethyloxycarbonyl) protecting group from the amino terminus of resin-bound amino acids. This deprotection occurs under mild basic conditions, typically with 20% piperidine in DMF, without affecting other orthogonal protecting groups on side chains. The resin support enables efficient washing steps to remove byproducts like dibenzofulvene, preventing side reactions and enhancing purity and yield in automated synthesizers. It is essential for the stepwise assembly of peptides and is widely applied in the synthesis of therapeutic peptides, proteins, and pharmaceutical intermediates requiring precise control over deprotection.