普鲁卡因酰胺N-乙酰基转移酶：氯贝丁酯和微粒体形式的调节作用

Procainamide N-acetyltransferase: modulation by clofibrate and a microsomal form.

Kang E S, Deaton P R, Epstein D, Ingram L A, Mirvis D M

Department of Pediatrics, University of Tennessee, Memphis 38163.

Gen Pharmacol. 1989;20(2):223-7. doi: 10.1016/0306-3623(89)90020-7.

Abstract

Detoxification of procainamide by N-acetyltransferase which occurs primarily in the cytoplasmic fraction of the rat liver can be modulated by clofibrate treatment. 2. When the concentration of one of the substrates, procainamide, is 100 microM while the other, acetyl CoA, is 10 or 100 microM, the specific activity is reduced following clofibrate treatment. However, total activity is unchanged because of a 44% increase in cytoplasmic protein. 3. At more physiological levels of the two substrates (10 microM), total enzyme activity is increased from 9.5 +/- 1.5 to 14.0 +/- 1.8 pmol/mg/min, P less than 0.05. 4. A microsomal form of N-acetyltransferase activity is reported which is unaffected by the concentration of acetyl CoA in contrast to the cytoplasmic form.

摘要

主要发生在大鼠肝脏细胞质部分的N - 乙酰转移酶对普鲁卡因胺的解毒作用可通过氯贝丁酯处理进行调节。2. 当其中一种底物普鲁卡因胺的浓度为100微摩尔，而另一种底物乙酰辅酶A的浓度为10或100微摩尔时，氯贝丁酯处理后比活性降低。然而，由于细胞质蛋白增加了44%，总活性保持不变。3. 在两种底物更接近生理水平（10微摩尔）时，总酶活性从9.5±1.5皮摩尔/毫克/分钟增加到14.0±1.8皮摩尔/毫克/分钟，P小于0.05。4. 据报道，存在一种微粒体形式的N - 乙酰转移酶活性，与细胞质形式不同，它不受乙酰辅酶A浓度的影响。