Graef V, Furuya E, Nishikaze O
Clin Chem. 1977 Mar;23(3):532-5.
We determined the enzymic activity of beta-glucuronidase preparations from bovine liver, Helix pomatia, and Escherischia coli with steroid glucuronides and nonsteroid glucuronides as substrates. We also studied the effect of Na2SO4 on the enzymic hydrolysis of several substrates with the three preparations of beta-glucuronidase. Na2SO4 increases the rate of hydrolysis of all substrates with beta-glucuronidase from bovine liver. Hydrolysis of a steroid glucoronide with beta-glucuronidase from Helix pomatia and E. coli is inhibited by Na2SO4. None of the three enzyme preparations gives complete hydrolysis of urinary steroid conjugates, because urine contains inhibitors, which can be removed by absorption chromatography of the urine on a column of neutral polystyrene resin Amberlite XAD-2. But when Amberlite XAD-2 is not used, hydrolysis of urinary glucuronides of androsterone, etiocholanolone, pregnanediol, estriol, and 17-hydroxycorticosteroids proves that, given an incubation time of 24 h, the beta-glucuronidase preparation from bovine liver, in the presence of Na2SO4, is suited for determining all of the above steroids except esriol; the preparation from Helix pomatia is good for determining estriol and 17-hydroxycorticosteroids; the preparation from E. coli is good for determining androsterone, 17-hydroxycorticosteroids, and especially estriol, the glucuronide, of which is maximally hydrolyzed in 2 h.
我们以甾体葡糖醛酸苷和非甾体葡糖醛酸苷为底物，测定了来自牛肝、苹果螺和大肠杆菌的β-葡萄糖醛酸酶制剂的酶活性。我们还研究了Na2SO4对这三种β-葡萄糖醛酸酶制剂催化几种底物水解的影响。Na2SO4可提高牛肝β-葡萄糖醛酸酶对所有底物的水解速率。Na2SO4可抑制苹果螺和大肠杆菌的β-葡萄糖醛酸酶对甾体葡糖醛酸苷的水解。这三种酶制剂均不能使尿甾体结合物完全水解，因为尿液中含有抑制剂，可通过将尿液在中性聚苯乙烯树脂Amberlite XAD - 2柱上进行吸附色谱法去除。但是，当不使用Amberlite XAD - 2时，对雄甾酮、本胆烷醇酮、孕二醇、雌三醇和17 - 羟基皮质类固醇的尿葡糖醛酸苷的水解证明，在24小时的孵育时间下，存在Na2SO4时，牛肝β-葡萄糖醛酸酶制剂适用于测定除雌三醇外的上述所有类固醇；苹果螺的制剂适用于测定雌三醇和17 - 羟基皮质类固醇；大肠杆菌的制剂适用于测定雄甾酮、17 - 羟基皮质类固醇，尤其是雌三醇，其葡糖醛酸苷在2小时内可被最大程度地水解。
