Hydrolyzes phosphonopyruvate. Not active towards phosphoenolpyruvate, glycerophosphate, phospho-L-serine or phosphoglycolic acid. 3-phosphonopyruvate + H2O = H(+) + phosphate + pyruvate Divalent metal cations. Co(2+), Mg(2+) or Mn(2+) can be used. Partially inhibited by EDTA. Activity is restored by Co(2+), and to a lesser extent by Ni(2+) and Mg(2+). Unaffected by Cs(2+) and Ca(2+). Activity is reduced by Mn(2+) and Cu(2+). Optimum pH is 7.0. Active from pH 6.0 to 9.0. Homodimer (PubMed:12697754). Homotetramer (PubMed:16981709). By phosphonoalanine or phosphonopyruvate. Belongs to the isocitrate lyase/PEP mutase superfamily. PEP mutase family.