Here we present data on the anticholinesterase activity of 58 synthesized ethers of phosphorus thioacids with an acetylene bond in the thioether group. Anticholinesterase activity of the compounds, with acetylene group in beta and especially alpha position, in the thioether radical is many times that of their saturated analogs. Reaction between the enzymes and acetylene organophosphorous inhibitors, as well as their saturated analogs, results in phosphorylated enzyme. The triple bond plays a significant role in the acceleration of cholinesterases phosphorylation. Antienzyme activity of acetylene organophosphorous inhibitors is discussed.

Acetylcholinesterase↗

PubMedDate not supplied

[The role of cytochrome p450 in metabolism of S-ethynylthiophosphates].

We studied interaction between S-ethynyl ethers of phosphorus acids with cytochrome P-450 from rat liver and housefly abdomen. High thionic effect, i.e., considerable selectivity for the studied compounds in homoiotherms and arthropods, proved to the related to the triple bond in these compounds. Apparently, cytochrome P-450 participates in S-ethynylthiophosphates metabolism and breaks the P-S bond. This gives rise to "self-destroying" metabolites, namely, alkylthioketenes, which decelerate deactivation reactions through destruction of the corresponding isoform of cytochrome P-450 in the microsomal fraction in both homoiotherms and insects. However, the activation reaction goes much faster in insects than in homoiotherms.

Alkynes↗

PubMedDate not supplied

[Analysis of kinetics of the combined inhibition of cholinesterases].

In the paper the analysis of the possible kinetic schemes is performed for the process of the combined inhibition of cholinesterases. It is shown that the considered schemes result in the identical experimental dependencies of the inhibition constants from the concentration of the inhibitor. Based on the analysis of about 200 experiments a linear dependence was found between logarithms of constants describing the reversible and irreversible action of the inhibitor.

Cholinesterase Inhibitors↗

PubMedDate not supplied

[O-ethyl-S(omega-carbalkoxyalkyl)methylthiophosphonates as cholinesterase inhibitors].

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Chemical Phenomena↗

PubMedDate not supplied

[Effect of substituted thiobutinylic esters of phosphorus thio acids and their saturated analogs on cholinesterases of different origins].

Studies have been made of the effect of organophosphorus inhibitors (OPI) containing butynilic group in the detectable part of the molecule, and of their saturated analogues on cholinesterases from different species of mammals and arthropods. In all cases without a single exception, acetylene compounds exhibited higher anticholinesterase effect than saturated ones. The value of "acetylene effect" varied to a great extent and depended on both the structure of OPI and the source of cholinesterase, these data indicating the existence of differences in the structure of the active site in cholinesterases investigated. The acetylene effect was always higher in ethylmercapto-substituted OPI than in chloride-substituted ones. Among thiophosphates, the highest (7,600) effect was found for cholinesterase of the spider mite in the case of dimethyl esters. Among thiophosphonates, exceptionally high (38,000) effect was noted for cholinesterase from the head of the domestic fly when methylthiophosphonates were compared. In this pair of compounds, the inhibitory constant k2 for the cholinesterase of the fly by acetylene derivative was equal to 1.1 . 10(9).

Acetylcholinesterase↗

PubMedDate not supplied

[Stereospecific action of organothiophosphate amino acid derivatives on nervous system esterase activity in the cockroach].

The effect of optic isomers of Rp- and Sp-CH3(C2H5O)P(O)SCH2C(O)NHCH5-COOC2H5(EH-13), Rc- and Sc-(C2H5O)2P(O)SCH2C(O)NHCH (i-C3-H7)COOC2H5.(SH.-156), RpRc-, SpSc-, and SpRc-CH3(C2H5O)P(O) SCH2C(O)NHCH(i-C3H7)-COOC2H5(Sh.-142) on the fraction composition of esterases from the nervous tissue of American cockroach was investigated. Esterases were separated by polyacrylamide gel disc-electrophoresis. Sp-(EH-13) and Rc-(Sh.-156) were shown to inhibit carboxy esterase to a greater extent than their antipodes. Stereoisomers of the substance (Sh.-142) were found to influence activity of carboxy esterase molecular forms in a different way. It is postulated that the active surface of molecules of certain carboxy esterase isoenzymes may have stereospecific structure.

Amino Acids↗

PubMedDate not supplied

Prospects for developing and improving a chemical method of pest control in the next 10 to 15 years.

The assortment of chemical substances for pest control which exists in the world or is planned by us, and the reserves which exist in scientific research make it possible to assert that: 1) It is possible to produce an assortment of pesticides that is practically harmless for man and useful animals; 2) it is possible to eliminate the accumulation of pesticides and their residue in the environment, in food products, and in food chains; 3) it is possible to produce highly selective pesticides which will not damage useful inhabitants of the biosphere, particularly useful arthropods and soil microorganisms; 4) it is possible with the proper technical approaches, especially with proper alternation of pesticides, to avoid the development of resistant strains of pests. This requires continuation of intensive scientific and technical investigations both of the pesticides themselves and in producing integrated systems with the use of an entire complex of means and methods for protecting the harvest, and improving the technical means of application.

Agriculture↗

PubMedDate not supplied

[Clinical study and therapeutic use of phosphonic compounds].

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Humans↗

PubMedDate not supplied

[The interaction of phoscarban with the esterases of houseflies and synanthropic cockroaches].

Interactions of phoscarban and its "oxon" with the esterase complex of the house-fly imago and four species of synanthropic cockroaches were studied. Phoscarban and its oxon have a wide spectrum of effects on the esterase complex in cockroaches and flies. These compounds are not specific inhibitors of any of the zones of esterase activity. Their insecticide effect depends on their ability to inhibit both choline esterases, which are responsible for nervous activity, and carboxyl esterases, which are involved in the detoxication of these compounds. We studied the species specificity of the esterase complex, including individual types and fractions, to phoscarban and its oxon in the order Dictyoptera. It was especially distinct for membrane-bound and water-soluble forms of choline esterases.

Animals↗