Formation of a carbon-phosphorus bond by converting phosphoenolpyruvate (PEP) to phosphonopyruvate (P-Pyr). H(+) + phosphoenolpyruvate = 3-phosphonopyruvate Secondary metabolite biosynthesis; bialaphos biosynthesis. Belongs to the isocitrate lyase/PEP mutase superfamily. PEP mutase family.