Leonards K S
Department of Physiology, University of California, School of Medicine, Los Angeles 90024.
Biochim Biophys Acta. 1988 Feb 18;938(2):293-309. doi: 10.1016/0005-2736(88)90167-8.
The cation-binding characteristics of isolated sarcolemmal vesicles from rat and canine cardiac muscle cells were investigated. To help elucidate the molecular properties involved in these interactions the cation-induced aggregation behavior of rat and canine cardiac sarcolemmal vesicles, sonicated unilamellar vesicles (SUVs) made from sarcolemmal lipid extracts, and SUVs generated from combinations of synthetic lipids similar to those found in the sarcolemmal membrane, as well as mitochondrial and sarcoplasmic reticulum enriched membrane fractions were examined. Our results indicate that cations, such as Ca2+, to indeed bind to the sarcolemmal membrane surface. They also suggest that two (or more) interacting sites are involved in the Ca2+-induced aggregation of the isolated sarcolemmal vesicles, and that sarcolemmal lipid components could be the primary binding sites. The modulating (secondary) sites on the other hand may be protein or carbohydrate in nature, or require specific lipid organizational properties. Finally, the results indicate that the interactions of cations, such as Ca2+, with the sarcolemmal surface are species specific, with the sarcolemmal membranes of both rat and canine preparations having different physico-chemical properties.
研究了从大鼠和犬心肌细胞分离出的肌膜囊泡的阳离子结合特性。为了有助于阐明这些相互作用中涉及的分子特性，研究了大鼠和犬心肌肌膜囊泡、由肌膜脂质提取物制成的超声处理单层囊泡（SUVs）、由与肌膜中发现的脂质类似的合成脂质组合产生的SUVs以及富含线粒体和肌浆网的膜组分的阳离子诱导聚集行为。我们的结果表明，阳离子，如Ca2+，确实与肌膜表面结合。它们还表明，两个（或更多）相互作用位点参与了Ca2+诱导的分离肌膜囊泡的聚集，并且肌膜脂质成分可能是主要结合位点。另一方面，调节（次要）位点可能本质上是蛋白质或碳水化合物，或者需要特定的脂质组织特性。最后，结果表明，阳离子，如Ca2+，与肌膜表面的相互作用具有物种特异性，大鼠和犬制剂的肌膜具有不同的物理化学性质。
