Wang G F, Cao Z F, Zhou H M, Zhao Y F
Department of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, People's Republic of China.
Int J Biochem Cell Biol. 2000 Aug;32(8):873-8. doi: 10.1016/s1357-2725(00)00027-3.
The activity and the conformational changes of methanol dehydrogenase (MDH), a quinoprotein containing pyrrolo-quinoline quinone as its prosthetic group, have been studied during denaturation in guanidine hydrochloride (GdnHCl) and urea. The unfolding of MDH was followed using the steady-state and time resolved fluorescence methods. Increasing the denaturant concentration in the denatured system significantly enhanced the inactivation and unfolding of MDH. The enzyme was completely inactivated at 1 M GdnHCl or 6 M urea. The fluorescence emission maximum of the native enzyme was at 332 nm. With increasing denaturant concentrations, the fluorescence emission maximum red-shifted in magnitude to a maximum value (355 nm) at 5 M GdnHCl or 8 M urea. Comparison of inactivation and conformational changes during denaturation showed that in general accord with the suggestion made previously by Tsou, the active sites of MDH are situated in a region more flexible than the molecule as a whole.
甲醇脱氢酶（MDH）是一种以吡咯喹啉醌为辅基的醌蛋白，研究了其在盐酸胍（GdnHCl）和尿素变性过程中的活性和构象变化。采用稳态和时间分辨荧光方法跟踪MDH的去折叠过程。增加变性体系中的变性剂浓度显著增强了MDH的失活和去折叠。该酶在1 M GdnHCl或6 M尿素中完全失活。天然酶的荧光发射最大值在332 nm处。随着变性剂浓度的增加，荧光发射最大值在5 M GdnHCl或8 M尿素时发生红移，幅度最大可达355 nm。变性过程中失活和构象变化的比较表明，总体上与邹以前提出的观点一致，MDH的活性位点位于比整个分子更灵活的区域。
