L-Phenylalanine-13C9,15N,d8 is the deuterium, 13C-, and 15-labeled L-Phenylalanine. L-Phenylalanine ((S)-2-Amino-3-phenylpropionic acid) is an essential amino acid isolated from Escherichia coli. L-Phenylalanine is a alpha2delta subunit of voltage-dependent Ca+