title: Studies on the Spectral Properties of Choline Dehydrogenase.
abstract: The addition of the substrate didn't show any influence on the intrinsic emission spectra of purified CDH, which had a maximum at 335 nm. On the other hand, the 520 nm fluorescence of CDH increased after the addition of substrate. The secondary structure of solubilized CDH was examined by Fourier-transform infrared spectroscopy. The percentage distribution of its secondary structure assignment had been obtained: 53.4% alpha-helix, 24.5% beta-sheet, 13.9% 3(10)-helix and 0.5% beta-turn. The predominant conformation of CDH was alpha-helix and beta-sheet when there was no substrate. After the addition of substrate, the percentage of 3(10)-helix structure increased to 42%, whereas that of alpha-helix structure decreased to 35%, indicating that the conformation of CDH changed significantly after the binding of substrate of substrate to the enzyme.
authors.affiliation: State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031,China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Fu
authors.forename: Qi-Shui
authors.initials: QS
authors.lastname: Lin