Choline Acetyltransferase in Skeletal Muscle from Patients with Myasthenia Gravis
Choline Acetyltransferase in Skeletal Muscle from Patients with Myasthenia Gravis
复制标题
重症肌无力患者骨骼肌中的胆碱乙酰转移酶
DOI：
10.1111/j.1471-4159.1981.tb04657.x
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发表时间：
1981
影响因子：
4.7
通讯作者：
A. Vincent
中科院分区：
文献类型：
--
作者：
P. Molenaar;J. Newsom;R. L. Polak;A. Vincent
摘要：采用放射化学方法测定人肋间肌匀浆中乙酰胆碱的合成。对照肌肉中的胆碱乙酰转移酶活性约为 20 nmol.g−1.h−1。这种酶仅存在于肌肉的终板区域。在高底物浓度下，其活性被另一种不被 10 mm 胆碱饱和的酶的乙酰胆碱合成活性所掩盖。非特异性酶存在于终板区域或远离终板区域。重症肌无力患者肋间肌胸骨旁样本中的胆碱乙酰转移酶比对照患者取自更外侧位置的样本中的胆碱乙酰转移酶高约 2.5 倍，但胆碱的 Km 没有改变 (0.24 mm)。有人认为，在重症肌无力中，乙酰胆碱受体的缺乏可以通过递质的合成、储存和释放的增加来部分补偿。
Abstract— Acetylcholine synthesis in homogenates of human intercostal muscle was measured by a radiochemical method. Choline acetyltransferase activity in control muscle was about 20 nmol.g−1.h−1. The enzyme was found only in the endplate area of the muscle. At high substrate concentrations its activity was overshadowed by the acetylcholine synthesizing activity of a different enzyme not saturated by 10 mm‐choline. The nonspecific enzyme was present at and away from the endplate area. Choline acetyltransferase in parasternal samples of intercostal muscle from myasthenia gravis patients was about 2.5 times higher than in samples, taken from a more lateral location, of control patients, but the Km for choline was not altered (0.24 mm). It is suggested that in myasthenia gravis the shortage of acetylcholine receptors is partially compensated for by increased synthesis, storage, and release of the transmitter.