Tiliabaev Z
Biokhimiia. 1979 Nov;44(11):2083-93.
The activity of locust ganglia cholinesterase is found to depend on concentrations of acetylthiocholine (ATC), propionylthiocholine (PTC) and butyrylthiocholine (BTC); that of carboxylesterase--on concentration of p-nitrophenylacetate (25 degrees, pH 7,5). The activity of cholinesterase is inhibited by an excess of ATC and BTC, but is unaffected by an excess of PTC. At concentrations greater than 0.01 M PTC is hydrolyzed faster than ATC at optimal (1.10(-3) M) concentration. The cholinesterase hydrolysis of BTC proceeds slower than that of ATC and PTC. The bimolecular constants (kII) of the rate of cholinesterase and carboxylesterase interaction with structurally different organophosphorus inhibitors (OPI) were determined. It was found that methylsulfomethylates of O-alkyl-S (beta-ethylmercaptoethyl) methylthiophosphonates are stronger inhibitors of cholinesterase than carboxylesterase; on the contrast, their uncharged analogs are stronger inhibitors of carboxylesterase, since the substitution of the sulfide sulphur for the sulphonic one strongly decreases the anticholinesterase activity and slightly increases the anticarboxylesterase activity of these OPI. O-alkyl-S (carbomethoxymethylmercaptomethyl) methylthiophosphonates inhibit carboxylesterase stronger than cholinesterase. The inhibitory activity of diisopropylthiophosphates towards cholinesterase is much lower than that of the corresponding diethylthiophosphates, while the activity of the former towards carboxylesterase is approximately the same as the activity of diethylthiophosphates or more strongly pronounced. Diisopropylfluorophosphate is a potent inhibitor of carboxylesterase. The data obtained provide evidence for differences in the structure of the active sites of cholinesterase and carboxylesterase. The carboxylesterase has no anionic sites. Moreover, the active surface of this enzyme interacting with the leaving part of OPI possesses, a site which prevents the absorption of cationic OPI and favours the interaction with the OPI containing the carboxyether group. The esterastic site of carboxylesterase is larger than that of cholinesterase and can predominantly interact with OPI having a bulky phosphoryl part.
已发现蝗虫神经节胆碱酯酶的活性取决于乙酰硫代胆碱（ATC）、丙酰硫代胆碱（PTC）和丁酰硫代胆碱（BTC）的浓度；羧酸酯酶的活性则取决于对硝基苯乙酸的浓度（25℃，pH 7.5）。胆碱酯酶的活性会被过量的ATC和BTC抑制，但不受过量PTC的影响。在浓度大于0.01 M时，在最佳浓度（1.10⁻³ M）下，PTC的水解速度比ATC快。BTC的胆碱酯酶水解速度比ATC和PTC慢。测定了胆碱酯酶和羧酸酯酶与结构不同的有机磷抑制剂（OPI）相互作用速率的双分子常数（kII）。发现O - 烷基 - S（β - 乙硫基乙基）甲基硫代膦酸酯的甲磺甲基化物对胆碱酯酶的抑制作用比对羧酸酯酶更强；相反，它们的不带电荷类似物对羧酸酯酶的抑制作用更强，因为用磺酸硫取代硫化硫会强烈降低这些OPI的抗胆碱酯酶活性，并略微增加其抗羧酸酯酶活性。O - 烷基 - S（甲氧羰基甲基巯基甲基）甲基硫代膦酸酯对羧酸酯酶的抑制作用比对胆碱酯酶更强。二异丙基硫代磷酸酯对胆碱酯酶的抑制活性远低于相应的二乙基硫代磷酸酯，而前者对羧酸酯酶的活性与二乙基硫代磷酸酯大致相同或更为显著。二异丙基氟磷酸酯是羧酸酯酶的有效抑制剂。所获得的数据为胆碱酯酶和羧酸酯酶活性位点结构的差异提供了证据。羧酸酯酶没有阴离子位点。此外，该酶与OPI离去部分相互作用的活性表面有一个位点，可阻止阳离子OPI的吸附，并有利于与含羧基醚基团的OPI相互作用。羧酸酯酶的酯解位点比胆碱酯酶的大，并且主要能与具有庞大磷酰基部分的OPI相互作用。
