L-Phenylalanine biochemically form proteins, coded for by DNA. It is neutral, and nonpolar because of the inert and hydrophobic nature of the benzyl side chain.
L-Phenylalanine is an essential α-amino acid with the formula C9H11NO2. It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine.