Orlov S N, Pokudin N I, Riazhskiĭ G G, Kravtsov G M
Biokhimiia. 1984 Jan;49(1):51-9.
It was shown that 3,3'-dipropylthiocarbocyanine iodide diS-C3-(5) can be used as a fluorescent probe for registration of conformational changes in calmodulin and troponin C, as well as for determination of concentrations of these Ca-binding proteins in experimental samples. The sensitivity of the method (10(-7) M) is only 5 times less than that of determination of calmodulin by phosphodiesterase and by 1 or 2 orders of magnitude more than that of other techniques based on conformational changes of the protein. The spectral parameters of the fluorescent probe allow to conduct the measurements in turbid media and in the presence of many other optically active substances. Evidence is given testifying the promiscuity of the use of this approach to the study of conformational changes in calmodulin under the action of Ca2+, Mg2+, monovalent cations, temperature and target proteins (troponin I, phosphodiesterase). using phosphodiesterase and Ca-ATPase, it was shown that under certain conditions diS-C3-(5) as well as other amphypathic compounds can modify the activity of calmodulin-dependent enzymes.
结果表明，3,3'-二丙基硫代碳菁碘化物diS-C3-(5)可作为一种荧光探针，用于记录钙调蛋白和肌钙蛋白C的构象变化，以及测定实验样品中这些钙结合蛋白的浓度。该方法的灵敏度（10(-7) M）仅比用磷酸二酯酶测定钙调蛋白的灵敏度低5倍，比基于蛋白质构象变化的其他技术高1至2个数量级。荧光探针的光谱参数允许在浑浊介质和许多其他光学活性物质存在的情况下进行测量。有证据证明，这种方法在研究钙调蛋白在Ca2+、Mg2+、单价阳离子、温度和靶蛋白（肌钙蛋白I、磷酸二酯酶）作用下的构象变化时具有通用性。使用磷酸二酯酶和钙ATP酶，结果表明在某些条件下，diS-C3-(5)以及其他两亲性化合物可以改变钙调蛋白依赖性酶的活性。
