Ochiai Yoshihiro, Watanabe Yoshiaki, Ozawa Hideo, Ikegami Shigeru, Uchida Naoyuki, Watabe Shugo
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Biosci Biotechnol Biochem. 2010;74(8):1673-9. doi: 10.1271/bbb.100290. Epub 2010 Aug 7.
Myoglobin (Mb) purified from fast skeletal muscle of bluefin tuna Thunnus thynnus orientalis was subjected to thermal treatment, and the denaturation profiles were examined by thermodynamic analysis. Based on the ellipticity or helical content obtained by circular dichroism (CD) spectrometry, it was found that denaturation of tuna Mb consisted of three steps, and that slight structural changes of Mb started below 20 degrees C. However, major structural changes were observed at around 58 and 72 degrees C. Differential scanning calorimetry (DSC) analysis revealed a similar but somewhat different thermal denaturation profile of Mb. In comparison with the denaturing profiles of whale Mb under the same conditions, the thermal stability of tuna Mb was found to be much lower. In the modeled tertiary structures of these Mbs, they were roughly similar to each other, though minor conformational differences were recognized and the total energy was found to be lower for tuna Mb.
从东方蓝鳍金枪鱼（Thunnus thynnus orientalis）快速骨骼肌中纯化得到的肌红蛋白（Mb）进行了热处理，并通过热力学分析研究了其变性曲线。基于圆二色光谱（CD）法测得的椭圆率或螺旋含量，发现金枪鱼肌红蛋白的变性分为三个步骤，并且在20℃以下肌红蛋白开始发生轻微的结构变化。然而，主要的结构变化发生在约58℃和72℃。差示扫描量热法（DSC）分析揭示了肌红蛋白类似但略有不同的热变性曲线。与相同条件下鲸肌红蛋白的变性曲线相比，发现金枪鱼肌红蛋白的热稳定性要低得多。在这些肌红蛋白的三级结构模型中，它们大致彼此相似，尽管存在微小的构象差异，并且发现金枪鱼肌红蛋白的总能量较低。
