Model of enniatin biosynthesis. The precursors d-hydroxycarboxylic acids and l-amino acids become activated at the A1- and the A2-domain of the enniatin synthetase ESYN. N-methylation of the amino acid takes place at the M-domain. The building blocks are transferred from one module to another by means of T-domains and are ultimately stored at the “waiting position” T2b. Condensation of the building blocks and final cyclization and release from the enzyme is catalyzed by the C-domains. Modified after .