Livingston D J, Watts D A, Brown W D
Arch Biochem Biophys. 1986 Aug 15;249(1):106-15. doi: 10.1016/0003-9861(86)90565-5.
Thermodynamic and kinetic parameters of the oxygenation and autoxidation reactions were determined for yellowfin tuna (Thunnus albacares), Pacific green sea turtle (Chelonia mydas caranigra), and sperm whale myoglobin. These proteins have quite similar heme contact residues, but vary in residues which are involved in globin stabilization and in postulated ligand paths to the heme iron. Oxygen equilibria measurements from 10 to 40 degrees C reveal that green sea turtle myoglobin has a lower oxygen affinity and lower enthalpy and entropy for oxygen-binding than the other proteins. Yellowfin tuna myoglobin has the most rapid oxygen dissociation rate and the highest susceptibility to autoxidation under all conditions studied. However, the dependence of the autoxidation rate on ionic strength is the same for the three proteins, despite substantial differences in their dynamic stabilities. These results suggest that the autoxidation reaction is more dependent on ligand accessibility than on the dynamic stability of the myoglobin.
测定了黄鳍金枪鱼（Thunnus albacares）、太平洋绿海龟（Chelonia mydas caranigra）和抹香鲸肌红蛋白的氧合和自氧化反应的热力学和动力学参数。这些蛋白质具有非常相似的血红素接触残基，但在参与球蛋白稳定的残基以及假定的通向血红素铁的配体路径方面有所不同。在10至40摄氏度范围内的氧平衡测量表明，绿海龟肌红蛋白与其他蛋白质相比，具有较低的氧亲和力以及较低的氧结合焓和熵。在所有研究条件下，黄鳍金枪鱼肌红蛋白具有最快的氧解离速率和最高的自氧化敏感性。然而，尽管这三种蛋白质的动态稳定性存在很大差异，但它们的自氧化速率对离子强度的依赖性是相同的。这些结果表明，自氧化反应更多地取决于配体的可及性，而不是肌红蛋白的动态稳定性。
