Garty H, Karlish S J
Methods Enzymol. 1989;172:155-64. doi: 10.1016/s0076-6879(89)72014-0.
The procedure we have described provides a simple, convenient, and sensitive method to assay conductive ion fluxes in membrane vesicles. It is particularly useful for detecting channels in heterogeneous populations of vesicles. The principal advantages are similar to those of sensitive enzyme assays, namely, screening for existence of channels in different membrane fractions, assaying purified channel proteins, large-scale testing of pharmacological agents, antibodies, etc. and in studies of macroscopic regulatory features, including channel activity or density in different states and interaction with regulatory ligands. In the future one can expect further applications in detecting synthesis of channel proteins, gene expression, etc. The tracer assay does not provide much information on molecular characteristics such as single-channel conductance, voltage sensitivity, and ion specificity. It therefore serves other purposes to those of the modern biophysical methods such as patch-clamp, noise analysis, and study of channels incorporated into bilayers.
我们所描述的方法提供了一种简单、便捷且灵敏的方法来测定膜囊泡中的导电离子通量。它对于检测囊泡异质群体中的通道特别有用。主要优点与灵敏的酶测定法相似，即筛选不同膜组分中通道的存在、测定纯化的通道蛋白、大规模测试药物制剂、抗体等，以及在宏观调节特征的研究中，包括不同状态下的通道活性或密度以及与调节配体的相互作用。未来有望在检测通道蛋白的合成、基因表达等方面有进一步的应用。示踪测定法无法提供关于单通道电导、电压敏感性和离子特异性等分子特征的太多信息。因此，它服务于与现代生物物理方法（如膜片钳、噪声分析以及对掺入双层膜中的通道的研究）不同的目的。
