<p>The biosynthetic schemes for the production of halogenated peptidic natural products offer avenues for the discovery of peptide halogenases, and opportunities for development of biocatalysts for derivatization of peptides and proteins. Here, a short review of recent discoveries regarding biocatalytic protein and peptide halogenation is provided. Halogenation in two major classes of peptidic natural products is discussed, those that are produced as ribosomal peptides and post translationally modified, and those that are produced by assembly line-like non ribosomal peptide synthetases. Mechanistic considerations and biocatalytic applications of peptide halogenases are briefly discussed.</p><p></p>