[Effect of cetyltrimethylammonium on the human blood cholinesterases activity].

The influence of cationic detergent cetyltrimethylammonium on the human blood cholinesterases activity (erythrocyte acetylcholinesterase and plasma butyrylcholinesterase) in reactions of hydrolysis of alpha-thionaphthylacetat and acetylthiocholine is studied. It is shown, that cetyltrimethylammonium is reversible effector for both cholinesterases. This compound competitively inhibited enzymatic hydrolysis of acetylthiocholine by both cholinesterases, and in the reactions of enzymatic hydrolysis alpha-thionaphthylacetat display as the synergistic activator--in experiments with butyrylcholinesterase, and as the reversible inhibitor--in experiments with acetylcholinesterase.

[The influence of pH on cholinesterase hydrolysis of alpha-naphthylacetate in the presence of some cationic detergents].

The influence of some cationic detergents on the catalytic activity of the horse blood plasma cholinesterase in reaction of hydrolysis of alpha-naphthylacetate at different pH were investigated. It was shown, that in the absence of detergents in acid pH of the reaction medium the Km value increases, but V remain constant. In the range of pH from 8.

[Effect of some isoquinoline alkaloids on enzymatic activity of acetylcholinesterase and monoamine oxidase].

It has been shown, that some benzo[c]-phenanthridine and diisoquinoline alkaloids isolated from Chelidonium majus L. and Macleaya (Bocconia) cordata and M. microcarpa (berberine, sanguinarine, chelidonine) and of drugs ("Ukrain" and "Sanguirythrine") inhibited the enzyme activity of acetylcholinesterase from human erythrocyte and monoamine oxidase from the rat liver.

[Comparative study of enzymatic activity of cholinesterases of different origin in thionaphthylacetate hydrolysis reactions].

A comparative determination of kinetic parameters V and Km in the reaction of hydrolysis thionaphthylacetate and well known substrate acetylthiocholine by choline esterases from different sources was conducted. It is shown that butyrylcholine esterases hydrolyze thionaphthylacetate with velocity comparable with that of hydrolysis of acetylthiocholine, while acetylcholine esterases and propionylcholine esterases hydrolyze this substrate several times slower than acetylthiocholine. The values of Km in the reactions of hydrolysis of thionaphthylacetate for all studied cholinesterases is an order higher than for acetylthiocholine except cholinesterase of blood serum of fish.

[Use of 1- and 2-thionaphthylacetates as cholinesterase substrates].

1- and 2-thionaphthylacetates were tested as cholinesterase substrates. It was shown that the butyrilcholinesterase from horse serum can hydrolize these compounds. The hydrolysis velocity of 1-thionaphthylacetate was comparable with hydrolysis velocity of acetylthiocholine (the well known cholinesterase substrate), but 2-thionaphthylacetate was hydrolysed more slowly.

[Method for determining nitrogen-containing cationic surface-active agents using butyrylcholinesterase].

The biochemical method for determination of cetyltrimethyl ammonium or cetylpyridinium, both being nitrogenated cationic surfactants, has been devised by using horse blood serum butyrylcholinesterase as analytical reagent. The method streams from the fact that surfactants tested are inhibitors of butyrylcholinesterase hydrolysis of butyrylcholin, a cationic substrate, but in this case they activate enzymatic hydrolysis of 1-naphthylacetate, a neutral substrate. Presence two opposite effects enlarges reliability to identifications.

[The inhibition enzymatic hydrolysis of acetylthiocholine by acetylcholinesterase using principal alkaloids isolated from celandine and macleya and their derivatives].

A study was made of a possible inhibitory action on the enzymatic hydrolysis of acetylthiocholine by human erythrocyte acetylcholinesterase of principal alkaloids isolated from Chelidonium majus L. and Macleaya (Bocconia) cordata and microcarpa (namely sanguinarine, chelidonine, berberine), and of drugs "Ukrain" (thiophosphoric acid derivative of a sum of the alkaloids isolated from Chelidonium majus L.) and "Sanguirythrine" (a mixture of unseparated closely related to benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine, isolated from Chelidonium majus L.

[Inhibition of cholinesterases of varying origin by ordinary and betaine vinylphosphates].

The comparative study of irreversible inhibitory action of some substituted vinyl-phosphates (in usual and betaine forms on cholinesterases from different biological sources such as the human blood erythrocytes, the horse and the hen blood serum and optic ganglia of the squid) has been carried out. It is shown that betaines obtain lesser inhibitory activity as compared with the corresponding ordinary vinylphosphates. Some of tested inhibitors display expressed selectivity of action.

[The reversible inhibition of cholinesterases from different biological sources by phosphonium betaines].

The action of some phosphonium betains on cholinesterases from different biological sources has been studied. It has been shown, that all studied betains are reversible inhibitors of cholinesterase hydrolysis of acetyltiocholine. Inhibiting action of these compounds on acetylcholinesterases is about ten times weaker that of the majority of known phosphonium salts, while their action on butyrylcholinesterases has no peculiarities.

[Interactions of various cationic detergents with cholinesterase of horse blood serum].

Cetyltrimethyl ammonium and cetylpyridinium, both being cationic detergents, have been studied for their effect on the catalytic activity of horse blood serum cholinesterase (BuHChE) in reactions of hydrolysis of carbonic acid esters. It is shown that the detergents tested are reversible competitive inhibitors of the reaction of butyryl cholinesterase hydrolysis of butyryl choline, a specific cationic substrate, but in this case they activate enzymic hydrolysis of alpha-naphthylacetate, a nonspecific neutral substrate. Values of constants, describing enzyme binding with a detergent, are estimated both by the degree of inhibition of enzymatic hydrolysis of butyryl choline and by the degree of activation of enzymatic hydrolysis of alpha-naphthylacetate and are practically equal.

[Comparative characterization of the catalytic properties of blood serum cholinesterase in pigeon and hen].

Significant difference in catalytic properties of partially purified cholinesterases from blood serum of pigeon and hen was shown by photometric method using Ellman's reagent. From eight studied thioesters, pigeon cholinesterase hydrolysed with the highest rate butyrylthiocholine but hen cholinesterase--propionylthiocholine. The enzymatic hydrolysis obeyed Michaelis-Menten equation only at low concentration of substrates up to 0.

[A kinetic study of the blood serum cholinesterase activity in the freshwater fish Abramis ballerus].

In reaction of hydrolysis of choline and thiocholine esters of carbonic acids at 25 degrees C, cholinesterase activity of the blood serum from the fish A. ballerus has been studied by modified Ellman's method and potentiometric titration method. The activity is maximal in pH region 7.

[Anticholinesterase activity of certain carboranyl-containing thio- and selenoesters of pentavalent phosphorus acids].

Anticholinesterase activity of carboranyl containing thio- and selenoesters of pentavalent phosphorus acids has been studied. Insertion of the carboranyl substituents in the thioester group of phosphororganic compounds was found to increase the anticholinesterase activity as compared with the thioalkyl analogues. The compounds with B-carboranyl group are less active inhibitors of cholinesterase than their isomers with C-carboranyl group.

[The mechanism of anticholinesterase action of acetylene organophosphorus inhibitors].

Introduction of the triple bond in the leaving group of the organophosphorus inhibitor molecule gives a sharp raise of the inhibitor activity but does not change principal characteristics of the cholinesterase inhibition mechanism. The reactivation experiments suggest that inactivation of cholinesterases by these compounds occurs due to phosphorylating of the serine hydroxyl by the corresponding phosphoric acid. A close similarity was shown between acetylenic and saturated organophosphorus inhibitors in altering ka upon change of pH and tetraalkylammonium ions action.