2-Cyano-D-phenylalanine (D-2-Cyanophenylalanine) is a substrate in enzymatic reactions, particularly in biochemistry and molecular biology. It is involved in synthesising peptides and proteins, serving as a building block for forming specific amino acid sequences. D-2-Cyanophenylalanine acts by participating in the formation of peptide bonds during protein synthesis, contributing to the structure and function of the resulting molecules. Its mechanism of action involves interacting with specific enzymes and ribosomes to facilitate the incorporation of the cyano-phenylalanine residue into the growing peptide chain.