Mannironi C, Cundari E, Bauer C, Del Carratore R, Bronzetti G, Corsi C, Nieri R, Paolini M
Mutat Res. 1985 Oct;147(5):231-5. doi: 10.1016/0165-1161(85)90063-9.
The effect of temperature on enzymatic activity and stability was studied with respect to the monooxygenase activities of aminopyrine-N-demethylase (APD) and p-nitroanisole O-demethylase (pNAD) under incubation conditions for the liver microsomal assay. The activities of S9 liver fractions of mice induced with sodium phenobarbital and beta-naphthoflavone were determined during a period of preincubation in a range of temperatures from 30 to 44 degrees C. The greatest value of the mean specific activity was found at 40-42 degrees C for both APD and pNAD. The rapid increase of lipid peroxidation after 1 h of incubation at temperatures higher than 42 degrees C can provide an explanation of the enhancement of the rate of inactivation. In order to determine whether biological response is affected by the modifications induced by temperature in the metabolic activating system, tester strain D7 of Saccharomyces cerevisiae was used to assay the genetic activity of the well known premutagenic agent cyclophosphamide by incubating the mixtures both at the traditional temperature of 37 degrees C and at 42 degrees C. We suggest that the use of more favourable conditions for LMA with respect to enzymatic activity, than the traditional ones could improve the reliability and the sensitivity of such tests.
在肝微粒体测定的孵育条件下，研究了温度对氨基比林 - N - 脱甲基酶（APD）和对硝基苯甲醚O - 脱甲基酶（pNAD）单加氧酶活性及稳定性的影响。在30至44摄氏度的温度范围内预孵育期间，测定了用苯巴比妥钠和β - 萘黄酮诱导的小鼠肝脏S9组分的活性。APD和pNAD的平均比活性在40 - 42摄氏度时均达到最大值。在高于42摄氏度的温度下孵育1小时后脂质过氧化的快速增加，可以解释失活速率的加快。为了确定生物反应是否受温度在代谢激活系统中诱导的修饰的影响，通过在传统的37摄氏度和42摄氏度下孵育混合物，使用酿酒酵母测试菌株D7来测定著名的前诱变剂环磷酰胺的遗传活性。我们建议，相对于传统条件，采用更有利于肝微粒体测定酶活性的条件可以提高此类测试的可靠性和灵敏度。
