McjC, we captured this substrate promiscuity (Figure .2): on the substrate (left) side, only residues for Gly1, Gly2, His5, Glu8, and Tyr20 were retained, while the remainder was represented as "any" amino acid (side chain not specified) or "any except glycine" (side chain of at least one carbon). On the product side, the isopeptide bond formation between Gly1 and Glu8 was specified. Therefore, this reaction SMARTS would match any peptide with the correct essential peptide length and amino acid pattern and introduce an isopeptide bond. As before, certain hydrogens were specified explicitly to prevent ambiguous matches (see entry reaction SMARTS). When chained together, MITE entries can therefore represent biosynthetic pathways in great detail, as here with the microcin J25 BGC.