Amino acid composition and methylation pattern of the enniatin family. Enniatins are composed of three d-hydroxycarboxylic acids and three l-amino acids. The structural diversity is defined by the incorporation of different l-amino acids (R1-R3), which can be valine (iPr), leucine (iBu) or isoleucine (sBu). l-amino acids can be methylated (Me, R4-R6). Modified after .