Connett R J, Hays E T
Am J Physiol. 1978 Jul;235(1):C25-34. doi: 10.1152/ajpcell.1978.235.1.C25.
In addition to a strophanthidin-sensitive (SS) sodium efflux, a large component of the sodium efflux in freshly isolated frog skeletal muscle is sodium-activated and strophanthidin-insensitive (SASI). The amount of metabolic energy associated with sodium movement by each of these components was measured and the coupling between sodium movement and adenosine 5'-triphosphate (ATP) hydrolysis in muscle was calculated. Energy production was blocked by iodoacetate and cyanide. Energy turnover was estimated from the change in creatine phosphate (CrP) and ATP contents and expressed as potential energy (PE = CrP + 2ATP). After metabolic poisoning a linear fall of PE occurred (6.3 mumol/g.h). Metabolic poisoning had no effect on the magnitude of the SS or SASI components of sodium efflux. In 2 h the sodium moved, and PE change due to the SS component was 4.35 and 1.66 mumol/g.h, respectively, which gave a coupling factor of 2.6. The amount of sodium moved by the SASI component was similar to that moved by the SS component in 2 h whereas no energy change was observed. It was, therefore, concluded that sodium movement by the SASI component requires no energy input.
除了对毒毛花苷敏感（SS）的钠外流外，新鲜分离的青蛙骨骼肌中钠外流的很大一部分是钠激活且对毒毛花苷不敏感（SASI）的。测量了与这些成分中每一种钠转运相关的代谢能量，并计算了肌肉中钠转运与腺苷5'-三磷酸（ATP）水解之间的偶联。能量产生被碘乙酸盐和氰化物阻断。根据磷酸肌酸（CrP）和ATP含量的变化估算能量周转率，并表示为势能（PE = CrP + 2ATP）。代谢中毒后，PE呈线性下降（6.3 μmol/g·h）。代谢中毒对钠外流的SS或SASI成分的大小没有影响。在2小时内，钠转运，SS成分导致的PE变化分别为4.35和1.66 μmol/g·h，耦合系数为2.6。SASI成分转运的钠量在2小时内与SS成分转运的钠量相似，而未观察到能量变化。因此，得出结论，SASI成分的钠转运不需要能量输入。
