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牛小脑突触膜GABA受体经非离子型去垢剂(Nonidet P40)溶液化和超滤分离后于4℃冰箱或0℃放置5天左右,其[~3H]-GABA特异结合活性(cpm/mg蛋白)较膜结合GABA受体提高115倍,该结合活性至少可维持20天。根据该蛋白与[~3H]-GABA特异结合的可饱和性、可逆性、高亲和部位的存在及其配基专一性等,表明它仍具备膜结合GABA受体的特征。该受体蛋白不具有[~3H]-氟硝基安定的结合活性,在7.5%聚丙烯酰胺凝胶电泳为单一染色区带,等电点5.2左右,SDS聚丙烯酰胺凝胶电泳显示两种亚基,主要亚基为4.4万道尔顿。对该受体蛋白的理化性质及分子量大小进行了初步观察。
Bovine cerebellar synaptic membrane GABA receptor was dissociated by nonionic detergent (Nonidet P40) and separated by ultrafiltration and stored in refrigerator at 4 ℃ or 0 ℃ for 5 days. The [~ 3H] -GABA specific binding activity (cpm / mg protein) was 115-fold more potent than the membrane-bound GABA receptor for at least 20 days. According to the saturation, reversibility, the presence of high affinity sites and the specificity of its ligand, the protein binds specifically to [~ 3H] -GABA, indicating that it still possesses membrane bound GABA receptor. The receptor protein does not have the binding activity of [~ 3H] -fluoronazoramine. The 7.5% polyacrylamide gel electrophoresis was a single staining zone with an isoelectric point of about 5.2. SDS polyacrylamide gel electrophoresis showed two The subunit, the major subunit is 44,000 Daltons. The physical and chemical properties of the receptor protein and molecular size were initially observed.