The structural analogs of α -aminoacids, α -aminophosphonic acids and their esters, are widely studied as biologically active substances [1]. At the same time, among the numerous publications of the last twenty years there are only a few communications devoted to biological activity of fluorinated α -aminophosphonates, although it is well known that inclusion of fluorine atoms and fluorine-containing substituents into molecules of organic substances results in profound changes of chemical and physicochemical properties and, consequently, the biological activity of these substances. In particular, it was shown that some fluorinated esters and phosphin-oxides inhibited cholinesterases [2, 3] and thrombin [4], in contrast to their nonfluorinated analogues.In this paper, the results of studies of interaction of fluorinated α -aminophosphonates (FAPs, 3a -3h ) with four serine hydrolases are presented. Compounds 3a -3h were synthesized according to the scheme shown below:The serine hydrolases that were studied in this work play an important role in determining the toxic action of organophosphorus compounds (OPs): acetylcholinesterase (AChE) is the target for acute cholinergic toxicity [5]; neuropathy target esterase (NTE) is the target for OP-induced delayed neuropathy (OPIDN) [6-8]; nonspecific esterases, butyrylcholinesterase (BChE) and carboxylesterase (CaE), are sites of loss (scavengers) for OPs that reduce the amount of an active compound reaching the primary targets [9], and in this way influence the character and severity of the toxic effect of OPs. A distinctive feature of FAPs as potential inhibitors of serine hydrolases is their lack of a typical leaving group (F, SR, OAr, etc.), as found in classic antiChE OPs.The molecular properties of FAPs and the mechanism whereby they interact with serine hydrolases were examined using kinetic studies, QSAR analysis, and theoretical molecular modeling, supported by data from X-ray crystallography and chemical reactivity studies.FAPs 3a -3h have been synthesized with yields of 60-90% by mixing ether solutions of equimolar amounts of the corresponding dialkylphosphite 1a -1h and sulfonylimine of hexafluoroacetone 2 with subsequent recrystallization of 3a -3h from petroleum ether. Yields, melting points, and NMR data of the synthesized compounds are presented in the table.Human erythrocyte AChE, horse serum BChE, and pig liver CaE (Sigma, USA) were used. A stable lyophilized hen brain NTE preparation obtained according to our method [10] was used as a source of NTE. AChE and BChE activities were assayed by Ellman's method using acetylthiocholine and butyryltiocholine as substrates. CaE activity was determined spectrophotometrically using p -nitrophenyl acetate as a substrate. NTE activity was determined by differential inhibition according to Johnson [6], using phenyl valerate as a substrate. For kinetic studies of enzyme inhibition, a
