Knowles A F, Racker E
J Biol Chem. 1975 Mar 10;250(5):1949-51.
Ca-2+-ATPase purified from sarcoplasmic reticulum of rabbit muscle forms a phsophoeznyme when exposed to inorganic phosphate in the presence of Mg-2+. On addition of ADP and Ca-2+ virtually all of the phosphate bound to the enzyme is transferred to form ATP. It has been shown previously and confirmed by us that (a) the purified ATPase contains one major polypeptide and about 30% phospholipids; (b) on removal of residual detergent by passage through Sephadex the enzyme forms vesicular membranes; and (c) these vesicles are leaky and incapable of accumulating Ca-2+. Our findings therefore indicate that we have observed ATP generation from ADP and P-i without the formation of an ion gradient across a membrane. We propose that the energy derived from ion-protein interaction drives the formation of ATP.
从兔肌肌浆网中纯化得到的Ca-2+-ATP酶，在Mg-2+存在的情况下暴露于无机磷酸盐时会形成磷酸酶。加入ADP和Ca-2+后，几乎所有与该酶结合的磷酸盐都会转移形成ATP。此前已有研究表明并经我们证实：（a）纯化的ATP酶含有一种主要多肽和约30%的磷脂；（b）通过葡聚糖凝胶去除残留去污剂后，该酶形成囊泡膜；（c）这些囊泡有渗漏现象，无法积累Ca-2+。因此，我们的研究结果表明，我们观察到了由ADP和P-i生成ATP的过程，且未形成跨膜离子梯度。我们提出，离子-蛋白质相互作用产生的能量驱动了ATP的形成。
