MULTIPLE MOLECULAR-FORMS OF ACETYLCHOLINESTERASE IN THE NEMATODE CAENORHABDITIS-ELEGANS
MULTIPLE MOLECULAR-FORMS OF ACETYLCHOLINESTERASE IN THE NEMATODE CAENORHABDITIS-ELEGANS
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DOI：
10.1111/j.1471-4159.1983.tb11811.x
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发表时间：
1983-01-01
影响因子：
4.7
通讯作者：
RUSSELL, RL
中科院分区：
文献类型：
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作者：
JOHNSON, CD;RUSSELL, RL
线虫C.线虫含有5种分子形式的乙酰胆碱酯酶（AChE）活性，其可以通过选择性溶解、速度沉降和离子交换色谱的组合来分离。这些被称为形式IA（5.2s）、形式IB（4.9s）、形式II（6.7s）、形式III（11.3s）和形式IV（13.0s）。除了III型以外，所有的都以显著的量存在于快速制备的提取物中，并且可能是天然的; III型可能是从IV型自溶而来的。大多数IA型和IB型可以通过重复提取而不使用去污剂来溶解; II型、III型和IV型需要去污剂来有效溶解，因此可能是膜结合的。高盐浓度对于这些形式的增溶不是必需的，并且也无助于增溶。对于所有的形式，MW和摩擦比进行了估计的凝胶渗透色谱法和速度沉降在H2O和D2 O的组合。分子量估计值范围为83，000 - 357，000;只有II型显示出广泛的不对称性。分离的形式进行了表征方面的底物亲和力，底物特异性，抑制剂的敏感性，热灭活，和洗涤剂的敏感性。根据这些性质判断，C.秀丽隐杆线虫与其他无脊椎动物一样，其胆碱酯酶形式与脊椎动物的真正或假胆碱酯酶都不相似。对C. elegans型清楚地将IA、III和IV型作为一组与IB和II型区分开来;因此，前者被指定为A类型，后者被指定为B类型。遗传证据表明，不同的基因控制A类和B类形式，这2类功能重叠。动力学性质、分子不对称性、分子大小和溶解度等因素都表明脊椎动物电器官中存在的多种胆碱酯酶形式的分子模型可能不适用于C.优雅的潜在的功能作用和亚基结构的多种乙酰胆碱酯酶形式在每个C。elegans类进行了讨论。
Extracts of the nematode C. elegans contain 5 molecular forms of acetylcholinesterase (AChE) activity that can be separated by a combination of selective solubilization, velocity sedimentation and ion-exchange chromatography. These are called form IA (5.2s), form IB (4.9s), form II (6.7s), form III (11.3s) and form IV (13.0s). All except form III are present in significant amounts in rapidly prepared extracts and are probably native; form III is probably derived autolytically from form IV. Most of forms IA and IB can be solubilized by repeated extractions without detergent; forms II, III and IV require detergent for effective solubilization and may therefore be membrane-bound. High salt concentrations are not required for, and do not aid in, the solubilization of these forms. For all forms, MW and frictional ratios were estimated by a combination of gel permeation chromatography and velocity sedimentations in H2O and D2O. The Mw estimates range from 83,000-357,000; only form II shows extensive asymmetry. The separated forms were characterized with respect to substrate affinity, substrate specificity, inhibitor sensitivity, thermal inactivation, and detergent sensitivity. Judging by these properties, C. elegans is like other invertebrates in that none of its cholinesterase forms resembles either the true or the pseudo cholinesterase of vertebrates. Internal comparison of the C. elegans forms clearly distinguishes forms IA, III and IV as a group from forms IB and II; the former are therefore designated class A forms, the latter class B forms. Genetic evidence indicates that separate genes control class A and class B forms, and that these 2 classes overlap functionally. Several factors, including kinetic properties, molecular asymmetry, molecular size and solubility, all suggest that a molecular model of the multiple cholinesterase forms oberved in vertebrate electric organs probably does not apply in C. elegans. Potential functional roles and subunit structures of the multiple AChE forms within each C. elegans class are discussed.