Hiromasa Y, Aso Y, Mayanagi K, Inoue Y, Fujisawa T, Meno K, Ueki T
Structural Biophysics Laboratory, The Institute of Physical and Chemical Research (RIKEN), Sayo-gun, Hyogo 679-5143.
J Biochem. 1998 Apr;123(4):564-7. doi: 10.1093/oxfordjournals.jbchem.a021973.
The limited proteolysis of the Bacillus stearothermophilus pyruvate dehydrogenase complex by V8 protease yields its core structure solely composed of lipoate acetyltransferase (E2) fragments. The changes in the core with guanidine hydrochloride (GdnHCl) were biphasic: below 0.8 M (first) and above 1.0 M (second) GdnHCl. The changes in the first phase were slight but significant: decreases in ellipticity and light scattering, and an increase in E2 activity. Insignificant changes in the molecular shape and size of the core were detected on fluorescence spectroscopy, ultracentrifugation, gel filtration, and electron microscopy. On the other hand, the changes in the second phase were drastic; the core was disassembled and denatured.
嗜热脂肪芽孢杆菌丙酮酸脱氢酶复合体经V8蛋白酶进行的有限蛋白水解产生了仅由硫辛酰胺乙酰转移酶（E2）片段组成的核心结构。核心结构在盐酸胍（GdnHCl）作用下的变化呈双相：在0.8 M（第一阶段）以下和1.0 M（第二阶段）以上的GdnHCl浓度下。第一阶段的变化轻微但显著：椭圆率和光散射降低，E2活性增加。通过荧光光谱、超速离心、凝胶过滤和电子显微镜检测到核心结构的分子形状和大小没有显著变化。另一方面，第二阶段的变化剧烈；核心结构被拆解并变性。
