PHOSPHORSAURE-BIS-[P-NITRO-PHENYLESTER] EIN NEUER HEMMSTOFF MIKROSOMALER CARBOXYLESTERASEN
PHOSPHORSAURE-BIS-[P-NITRO-PHENYLESTER] EIN NEUER HEMMSTOFF MIKROSOMALER CARBOXYLESTERASEN
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DOI：
10.1515/bchm2.1967.348.1.609
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发表时间：
1967-01-01
影响因子：
--
通讯作者：
KRISCH, K
中科院分区：
文献类型：
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作者：
HEYMANN, E;KRISCH, K
双-[对硝基苯基]磷酸酯与来自猪肝微粒体的高度纯化的羧酸酯酶制剂（EC 3.1.1.1）快速、不可逆且化学计量地反应。该产品是一种磷酸化的无活性酶衍生物。当抑制剂过量时，每摩尔酶释放两摩尔对硝基苯酚。这证实了早期使用E 600 [二乙基-对硝基苯基磷酸酯]进行的研究，该研究表明猪肝酯酶具有2个活性中心。来自牛肝和猪肾的另外两种羧酸酯酶也被双-[p-硝基-苯基]磷酸盐抑制。然而，[α]-糜蛋白酶、胰蛋白酶、乙酰胆碱酯酶和非特异性血清胆碱酯酶不受抑制。双-[对硝基苯基]磷酸酯（腹腔内）在小鼠中的LD 50为410 mg/kg。这种磷酸酯在体内也能阻断小鼠肝脏对单乙基甘氨酸-2，6-二甲基苯胺的水解。动力学研究表明，猪肝羧酸酯酶的第二活性中心与双-[p-硝基-苯基]磷酸酯的反应比第一活性中心慢10倍左右。测定了第一活性中心反应的活化焓和最适pH值。
Bis-[p-nitro-phenyl]phosphate reacts rapidly, irreversibly and stoichiometrically with a highly purified preparation of carboxylesterase (EC 3.1.1.1) from pig liver microsomes. The product is a phosphorylated, inactive enzyme derivative. With an excess of the inhibitor, two moles of p-nitro-phenol are released for each mole of enzyme. This confirms earlier studies with E 600 [diethyl-p-nitrophenyl phosphate] which indicated that pig liver esterase has 2 active centers. Two other carboxylesterases from bovine liver and from pig kidney are also inhibited by bis-[p-nitro-phenyl]phosphate. [alpha]-Chymotrypsin, trypsin, acetylcholinesterase and non-specific serum cholinesterase are, however, not inhibited. The LD50 for bis-[p-nitro-phenyl]phosphate (intraperitoneal) in the mouse is 410 mg/kg. The hydrolysis of monoethylglycine-2,6-xylidide by mouse liver is also blocked in vivo by this phosphate ester. Kinetic studies show that the 2nd active center of carboxylesterase from pig liver reacts about 10 times more slowly than the 1st with bis-[p-nitro-phenyl]phosphate. The activation enthalpy and pH-optima were measured for the reaction with the 1st active center.