DFP [Diisopropoxyphosphoryl fluoride] 
Studies showed that a DFPase was present in mammals and that it was 
capable of splitting the P-F bond and releasing HF. Phosphorylation of 
the serine moiety of the enzyme occurred simultaneously (51, 52, 719, 789, 
949, 1046, 1047, 1048, 1064, 1581). 
When small amounts (0.1 mg/kg) of DFP were administered to guinea 
pigs, DFP was preferentially bound by serum and by the lungs. Administration 
of large amounts (3-6 mg/kg) produced uniform body distribution and accumu- 
lation in kidneys and liver. DFP was converted in part to diisopropyl 
phosphate (DP). Both DFP and DP were excreted mainly in the urine. Some 
appeared in bile (293, 612). 
DFP was degraded by Pseudomonas melophthora but no metabolites were { 
identified (145). 
Bluegill (Lepomis macrochirus Rafinesque) and channel catfish 
(Ictalurus punctalus Walbaum) converted DFP to diisopropyl phosphate 
(1681). 

Hydrolysis 
Km (moles/1 V moles/m rotein/hr 
Bluegill ae 10. 13.62 
Catfish Bese SOR 9.72 
0 
, 
ee Ll? CH,0-P~(i-O0C.H_), 
CH Ha 0 H 
7 4 
3NcHo _ + ‘ RZ a Wr > + HF 
cH r NH \ Ue 
DFP 
142 

