Aliev M K, Levitskaia E L, Levchenko T S, Levitskiĭ D O
Biokhimiia. 1985 Jun;50(6):911-8.
Sarcoplasmic reticulum fragments were fractionated according to the ability of caffeine to selectively block Ca2+ uptake in the population of caffeine-sensitive membranes. The membrane suspension was loaded with calcium in the presence of oxalate, Mg-ATP and caffeine, after which the Ca2+-loaded caffeine-sensitive fragments were separated by sucrose density gradient centrifugation. In Ca2+-unloaded fragments of the supernatant, the sensitivity to caffeine estimated by its ability to diminish the rate of Ca2+ uptake, Ca/ATP ratio and Ca-oxalate capacity amounted to 91-93%. The terms of protein composition, the caffeine-sensitive fragments were identified with terminal cystern membranes, while the caffeine-insensitive ones with the SR canalicular membranes. The sensitivity to caffeine may serve as a reliable criterion for estimating the relative content of terminal cystern fragments in different microsomal preparations.
肌浆网片段根据咖啡因选择性阻断咖啡因敏感膜群体中Ca2+摄取的能力进行分级分离。在草酸盐、Mg-ATP和咖啡因存在的情况下，将膜悬浮液加载钙，之后通过蔗糖密度梯度离心分离加载Ca2+的咖啡因敏感片段。在上清液的未加载Ca2+片段中，通过其降低Ca2+摄取速率、Ca/ATP比值和草酸钙容量的能力估算的对咖啡因的敏感性达91-93%。就蛋白质组成而言，咖啡因敏感片段被鉴定为终末池膜，而咖啡因不敏感片段被鉴定为肌浆网小管膜。对咖啡因的敏感性可作为评估不同微粒体制剂中终末池片段相对含量的可靠标准。
