This family consists of examples of phosphoenolpyruvate phosphomutase, an enzyme that creates a C-P bond as the first step in the biosynthesis of natural products including antibiotics like bialaphos and phosphonothricin in Streptomyces species, phosphonate-modified molecules such as the polysaccharide B of Bacteroides fragilis, the phosphonolipids of Tetrahymena pyroformis, the glycosylinositolphospholipids of Trypanosoma cruzi. This gene generally occurs in prokaryotic organisms adjacent to the gene for phosphonopyruvate decarboxylase (aepY). Since the PEP phosphomutase reaction favors the substrate PEP energetically, the decarboxylase is required to drive the reaction in the direction of phosphonate production. Most often an aminotansferase (aepZ) is also present which leads to the production of the most common phosphonate compound, 2-aminoethylphosphonate (AEP). A closely related enzyme, phosphonopyruvate hydrolase from Variovorax sp. Pal2, is excluded from this model.