Diadiusha G P, Lesnaia L Ia
Ukr Biokhim Zh (1978). 1978 Jan-Feb;50(1):27-34.
The phospholipid, cholesterol, SH-group content and acethylcholinesterase activity in ultrasonic sarcolenima fragments precipitating at 105000 g were much greater than in fragments precipitating at 3000 g. On the basis of the results obtained it is suggested that the 3000 g sediment consists largely of network of collagen fibrils, while the 105 000 g sediment is mainly composed by the plasma membrane fragments. It is shown that the amount of SH-groups in intact sarcolemma available for 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNG) in the presence of sodium dodecylsulphate was about twice as much as that in the absence of sodium dodecylsulphate. As to the sonicated fractions of sarcolemma (sediment and supernatant at 105 000 g) and high ionic strength extract of sarcolemma the amount of SH-groups available for DTNB in the presence and in the absence of sodium dodecylsulphate was similar. A decrease was observed in acetylcholinesterase stability after sonication (sediment and supernatant at 105 000 g). The normal Michaelis kinetics was found for the acetylcholinesterase of sarcolemma fractions solubilized by sonication.
在105000 g下沉淀的超声肌膜碎片中的磷脂、胆固醇、巯基含量和乙酰胆碱酯酶活性远高于在3000 g下沉淀的碎片。根据所得结果表明，3000 g沉淀物主要由胶原纤维网络组成，而105000 g沉淀物主要由质膜碎片组成。结果表明，在十二烷基硫酸钠存在下，完整肌膜中可与5,5-二硫代双-(2-硝基苯甲酸)(DTNG)反应的巯基数量约为不存在十二烷基硫酸钠时的两倍。至于肌膜的超声处理部分(105000 g下的沉淀物和上清液)以及肌膜的高离子强度提取物，在存在和不存在十二烷基硫酸钠的情况下，可与DTNB反应的巯基数量相似。超声处理后(105000 g下的沉淀物和上清液)观察到乙酰胆碱酯酶稳定性下降。发现超声处理溶解的肌膜部分的乙酰胆碱酯酶具有正常的米氏动力学。
