New safe method for preparation of sarin-exposed human erythrocytes acetylcholinesterase using non-toxic and stable sarin analogue isopropyl p-nitrophenyl methylphosphonate and its application to evaluation of nerve agent antidotes.
BACKGROUND
A non-toxic and stable sarin analogue, isopropyl p-nitrophenyl methylphosphonate (INMP), was synthesized for safe preparation of sarin-exposed acetylcholinesterase (AChE).


CONCLUSIONS
This agent was stable for years, able to be handled in an ordinary laboratory without special care, and its 50% inhibitory concentration (IC50) on 0.04 U/ml human erythrocytes AChE was 15 nM. This reagent was thought to be especially useful since it enables experiments that require sarin-inhibited AChE, such as the development of antidotes for sarin, in a usual laboratory. To demonstrate the usefulness of this method, 40 known and novel pyridinealdoxime methiodide (PAM)-type oxime antidotes were synthesized, and their reactivation activities to INMP-exposed AChE and structure-activities correlation were studied.


CONCLUSIONS
Among the antidotes tested in this experiment except for 2-PAM, the compound found to have the highest reactivation activity, was the novel hydrophobic 2-PAM-type compound, 2-[(hydroxyimino)methyl]-1-[4-(tert-butyl)benzyl] pyridinium bromide.
Ohta
Hikoto
H
Toxicology Section, Department of Forensic Chemistry, National Research Institute of Police Science, Kashiwa, Chiba, 277-0882, Japan. ohta@nrips.go.jp
Ohmori
Takeshi
T
Suzuki
Shinichi
S
Ikegaya
Hiroshi
H
Sakurada
Koichi
K
Takatori
Takehiko
T
D000110:Acetylcholinesterase / Q000097:blood*; D000931:Antidotes / Q000494:pharmacology*; D002619:Chemical Warfare Agents / Q000494:pharmacology*; D002800:Cholinesterase Inhibitors / Q000097:blood / Q000494:pharmacology*; D002801:Cholinesterase Reactivators / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004912:Erythrocytes / Q000187:drug effects* / Q000201:enzymology*; D006801:Humans; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D012524:Sarin / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D013329:Structure-Activity Relationship
D000931:Antidotes; D002619:Chemical Warfare Agents; D002800:Cholinesterase Inhibitors; D002801:Cholinesterase Reactivators; D007202:Indicators and Reagents; D012524:Sarin; D000110:Acetylcholinesterase