Highly specific for phosphonopyruvate as substrate [2]. The reaction is not inhibited by phosphate but is inhibited by the phosphonates phosphonoformic acid, hydroxymethylphosphonic acid and 3-phosphonopropanoic acid [2]. The enzyme is activated by the divalent cations Co2+, Mg2+?and Mn2+. This enzyme is a member of the phosphoenolpyruvate mutase/isocitrate lyase superfamily [3].