1.13.11.73	E176H	site-directed mutagenesis, the HEPD, EC 1.13.11.72, mutant is bifunctional exhibiting the activity of both 2-hydroxyethylphosphonate dioxygenase (HEPD) and methylphosphonate synthase (MPnS). The product distribution of the mutant is sensitive to a substrate isotope effect, consistent with an isotope-sensitive branching mechanism involving a common intermediate. The introduced histidine does not coordinate the active site metal, unlike the iron-binding glutamate it replaces. More HEPD activity is observed when the reaction is carried out with (R)-2-[2-2H1]-hydroxyethylphosphonate	
1.13.11.73	Q152D	the mutant shows weakened activity compared to the wild type enzyme	
1.13.11.73	Q152E	inactive	
1.13.11.73	Q152H	the mutant shows weakened activity compared to the wild type enzyme