Biochemical Characterization of Two Forms of Phosphonoacetaldehyde Hydrolases from Organophosphonate-Degrading Soil Achromobacter Isolates

The present work contains the results of the biochemical characterization of phosphonoacetaldehyde hydrolases (phosphonatases) existing in two different conformations, which were isolated from organophosphonate-degrading bacteria Achromobacter aegrifaciens Km 11B and Achromobacter aegrifaciens Km 11C. The existence of the two forms of phosphonatase in A. aegrifaciens strains was demonstrated for the first time. Elution of the phosphonatases from A. aegrifaciens Km 11B and A. aegrifaciens Km 11C on an anion-exchange carrier resulted in two active peaks eluted at different NaCl concentrations. The kinetic characteristics and the dependence of the reaction rate on temperature and pH were determined, and the influence of various effectors on phosphonatase activity was studied. It was revealed that the second form of phosphonatase of A. aegrifaciens Km 11B and A. aegrifaciens Km 11C (PhnX11B-II and PhnX11C-II, respectively) was characterized by the formation of allosteric regulation centers.