Tritium labeling of a powerful methylphosphonate inhibitor of cholinesterase: synthesis and biological applications.
7-(Methylethoxy phosphinyloxy)-1-methyl-quinolinium iodide (MEPQ), a powerful anti-cholinesterase methylphosphonate ester, was labeled with tritium (9 Ci/mmol) at the methylphosphonyl moiety (TCH2P(O)(OR)X) by an iodine-tritium replacement reaction. Kinetic measurements of the rate of inhibition of acetylcholinesterase (AChE) by [3H]MEPQ and its rate of hydrolysis in alkaline solution confirmed the identity of [3H]MEPQ with authentic MEPQ, which was prepared by the same reaction sequences. Gel-filtration experiments verified the radiospecificity of [3H]MEPQ. In vitro radiolabeling of both AChE and butyrylcholinesterase along with the whole-body autoradiography of [3H]MEPQ-treated mice suggests that [3H]MEPQ is a convenient marker for studying biological systems containing these esterases.
Balan
A
A
Israel Institute for Biological Research, Ness-Ziona.
Barness
I
I
Simon
G
G
Levy
D
D
Ashani
Y
Y
D000110:Acetylcholinesterase; D000818:Animals; D001345:Autoradiography; D002091:Butyrylcholinesterase; D002800:Cholinesterase Inhibitors; D002850:Chromatography, Gel; D007553:Isotope Labeling; D051379:Mice; D011806:Quinolinium Compounds; D014316:Tritium
D002800:Cholinesterase Inhibitors; D011806:Quinolinium Compounds; D014316:Tritium; C044294:7-((methylethoxyphosphinyl)oxy)-1-methylquinolinium; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase