| OPH | 
        Specific activityab | 
        Fold-difference    compared to wild-type OPH  | 
       
      
        | Demeton-S methyl | 
        Malathion | 
        Demeton-S methyl | 
        Malathion | 
       
      
        | Wild-type OPH | 
        1.1x10-4 (0.68x10-4) | 
        1.0x10-4 (0.49x10-4) | 
        N/A | 
        N/A | 
       
      
        | S308L.OPH | 
        116.8x10-4 (0.50x10-4) | 
        37.1x10-4 (0.10x10-4) | 
        106.2 | 
        37.1 | 
       
     
      a μmoles hydrolyzed/min/mg total protein 
        b average of three independent lysates (standard deviation) 
     N/A, not applicable |