Several newly reported post-translational modification reactions are involved in lantibiotic biosynthesis. A short overview of the present knowledge on the post-translational modifications and on the enzymes involved in lantibiotic biosynthesis is given. The oxidative decarboxylation of the epidermin precursor peptide EpiA is described in detail. The FMN-containing oxidoreductase EpiD is involved in the formation of the C-terminal S-[(Z)-2-aminovinyl]-D-cysteine residue of epidermin: under reducing conditions the side chain of the C-terminal cysteine residue of EpiA is converted to an enethiol. EpiD has no absolute substrate specificity and can be used for modification of peptides having the C-terminal consensus motif [V/I/L/(M)/F/Y/W]-[A/S/V/T/C/(I/L)]-C.