MacLennan D H, Khanna V K, Stewart P S
J Biol Chem. 1976 Nov 25;251(22):7271-4.
When sarcoplasmic reticulum vesicles are exposed to trypsin for 1 min the adenosine triphosphatase (Mr = 102,000) is cleaved to fragments of Mr = 45,000 and 55,000. The purified ATPase, containing both fragments, transports Ca2+ when incorporated into vesicles containing excess phospholipid. The two fragments can only be dissociated in solutions containing 1% sodium dodecyl sulfate (SDS). Ca2+ transport activity is restored in SDS-dissociated preparations in a series of steps involving dilution with 5 volumes of 5% phospholipids in 0.75% sodium cholate, incubation in ice for 30 min, and passage through an anion exchange column. Vesicles formed in this procedure regain high Ca2+ transport activity if they are incubated in SDS solution at 24 degrees for less than 20 min. However, the extent of renaturation diminishes if the vesicles are incubated for longer periods and little acitivity is recovered in vesicles incubated longer than 60 min at 24 degrees.
当肌浆网囊泡暴露于胰蛋白酶1分钟时，腺苷三磷酸酶（分子量 = 102,000）被切割成分子量为45,000和55,000的片段。含有这两个片段的纯化ATP酶，当掺入含有过量磷脂的囊泡中时可转运Ca2+。这两个片段仅在含有1%十二烷基硫酸钠（SDS）的溶液中才能解离。在SDS解离的制剂中，通过一系列步骤可恢复Ca2+转运活性，这些步骤包括用5倍体积的0.75%胆酸钠中的5%磷脂稀释、在冰中孵育30分钟以及通过阴离子交换柱。如果在此过程中形成的囊泡在24℃的SDS溶液中孵育少于20分钟，它们会重新获得高Ca2+转运活性。然而，如果囊泡孵育时间更长，复性程度会降低，并且在24℃孵育超过60分钟的囊泡中几乎没有恢复活性。
