Background: Human prolidase has weak hydrolytic activity for toxic organophosphorus
compounds including diisopropyl fluorophosphates (DFP), chemical warfare nerve agents and pesticides.
Objectives: In order to use human prolidase as a catalytic bioscavenger against toxic organophosphorus
compound exposure, protein engineering is an important issue to improve the catalytic activity
of human prolidase towards the hydrolysis of toxic organophosphorus compounds.
Method: We developed two human prolidase mutants, A252R and P365R, with a single amino acid
substitution using in silico analysis based on the sequence, protein structure and stability to improve
the catalytic activity of human prolidase towards DFP hydrolysis.
Results: Our results showed that the catalytic efficiencies of A252R and P365R towards DFP hydrolysis
were 1.23- and 1.36-fold increases, respectively, than that of the wild type, while the prolidase
activities of A252R and P365R towards Leu-Pro hydrolysis were 0.88- and 0.78-fold decreases
that of the wild type, respectively, indicating that substitution mutations of A252R and
P365R in human prolidase show improved hydrolytic activity for toxic organophosphorus compounds.
Conclusion: We report here that by introducing either the A252R or P365R substitution mutation,
the structural changes affecting catalytic turnover rate and substrate binding affinity are valuable in
improving the catalytic activity of human prolidase towards toxic organophosphorus compound