Reinhardt R R, Wecker L
J Neurochem. 1983 Sep;41(3):623-9. doi: 10.1111/j.1471-4159.1983.tb04787.x.
The distribution of choline kinase (EC 2.7.1.32) activity was investigated in subcellular fractions of rat striatum. Enzyme activity in the crude mitochondrial fraction, determined after dissolution in Triton X-100, was 5.90 mumol/g initial wet weight/h. When a crude mitochondrial preparation was hypoosmotically shocked and fractionated, followed by the addition of Triton X-100, choline kinase activity in the soluble and particulate fractions was 4.58 and 1.40 mumol/g initial wet weight/h, respectively. Enzyme activity in the particulate fraction was not detected in the absence of Triton X-100 or in the presence of NaCl (up to 1.5 M). Subcellular enzyme markers indicated that the membrane-associated activity was not attributable to mitochondrial or microsomal contamination. Kinetic analysis of the activity of soluble and membrane-solubilized choline kinase indicated Km values of 0.74 mM and 0.68 mM, respectively. Results indicate that choline kinase activity may be measured in both the soluble and the particulate fractions of rat striatum, the latter most likely involving enzyme associated with membrane through hydrophobic or covalent interactions. The specific function of the membrane-associated enzyme has not yet been determined.
对大鼠纹状体亚细胞组分中的胆碱激酶（EC 2.7.1.32）活性分布进行了研究。在溶于 Triton X - 100 后测定的粗线粒体组分中的酶活性为 5.90 μmol/g 初始湿重/小时。当对粗线粒体制剂进行低渗冲击并分级分离，随后加入 Triton X - 100 时，可溶性和颗粒性组分中的胆碱激酶活性分别为 4.58 和 1.40 μmol/g 初始湿重/小时。在不存在 Triton X - 100 或存在 NaCl（高达 1.5 M）的情况下，未检测到颗粒性组分中的酶活性。亚细胞酶标志物表明，与膜相关的活性并非归因于线粒体或微粒体污染。对可溶性和膜溶解的胆碱激酶活性的动力学分析表明，Km 值分别为 0.74 mM 和 0.68 mM。结果表明，胆碱激酶活性可在大鼠纹状体的可溶性和颗粒性组分中进行测定，后者很可能涉及通过疏水或共价相互作用与膜相关的酶。与膜相关的酶的具体功能尚未确定。
