(582c) Enhanced Activity and Stability of Organophosphorus Hydrolase Via Interaction with an Amphiphilic Polymer

Authors: 
Kim, M., Massachusetts Institute of Technology
Gkikas, M., University of Athens
Huang, A., Massachusetts Institute of Technology
Kang, J. W., Massachusetts Institute of Technology
Suthiwangcharoen, N., Natick Soldier Research, Development & Engineering Center
Olsen, B. D., Massachusetts Institute of Technology

Neurotoxic organophosphate (OP) compounds are widely used as pesticides and, unfortunately, as chemical warfare agents. A decontamination system based on organophosphorus hydrolase (OPH) is of great interest due to its potential for non-toxic and non-corrosive decontamination of OPs. However, despite its high catalytic activity, OPH has a relatively short shelf-life and low stability under practical working environments, such as pot life, organic solvents, and high temperatures. 

Here, a simple approach to enhancing the activity and stability of OPH has been developed based on interactions between the hydrophobic poly(propylene oxide) (PPO) block of the amphiphilic block copolymer Pluronic and the enzyme.  Using MALDI-TOF, NMR, Raman and fluorescence spectroscopies, evidence is provided that the PPO block of the polymer can interact with hydrophobic amino acids of OPH near its active site.

The polymer in pre-constructed OPH/Pluronic complexes enhances the stability and activity of the enzyme (i) in aqueous solutions with low enzyme concentration at RT (pot life), (ii) in the presence of an organic solvent (iii) in aqueous solutions at higher temperatures, (iv) after lyophilization, and (v) during long-term storage.  PPO-containing block copolymers with various molecular structures have also been demonstrated to enhance OPH stability and its activity. Therefore, this strategy of simply blending enzyme with inexpensive, non-toxic, biocompatible, and commercially available Pluronic provides an efficient route to new formulations for decontaminating organophosphate neurotoxins.