p-Ethynylphenylalanine hydrochloride（Cat No.:I045047）is a synthetic, non-natural amino acid derivative of phenylalanine, featuring an ethynyl group at the para-position of the aromatic ring. Supplied as a hydrochloride salt, it is commonly used in peptide synthesis, protein engineering, and bioorthogonal chemistry. The terminal alkyne group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), allowing site-specific labeling or conjugation to biomolecules. This compound is valuable for studying protein structure, dynamics, and function, and is widely used in the design of modified peptides, therapeutic candidates, and molecular probes in chemical biology.