title: [UV-Vis absorption spectral characteristics of tobacco peroxidase I from Nicotiana tabacum].
abstract: The ultraviolet/visible spectra of TOP I were studied. It was proved that TOP I is an acid enzyme containing it hemochrome as an agon. When the pH reduced, the Soret absorption in UV-Vis region exhibited a blue shift, when pH increased exhibited a red shift. The result of the influence of carbamide, the denaturant, on the spectra showed that TOP I may have a unfolded structural change in the solution, which made the peptide chain completely extend. After adding Fe(III), Fe(II), Cu(II), Zn(II), Co(II), Ni(II) and Sn(II) to the apo-TOP I, the UV-Vis spectra changed except for Fe(III), which almost did not change at all. The strongest characteristic absorption peak of the Soret showed a blue shift to different extent and it became weak gradually. The situation of alpha-strip and beta-strip remained unchanged while the relative strength decreased.
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Bing-le
authors.initials: BL
authors.lastname: Xia
authors.forename: Min-Li
authors.initials: ML
authors.lastname: Li
authors.forename: Qing-liang
authors.initials: QL
authors.lastname: Liu
authors.forename: Xiao-lan
authors.initials: XL
authors.lastname: Zhu
mesh_terms: D002942:Circular Dichroism / Q000379:methods; D008958:Models, Molecular; D015394:Molecular Structure; D010544:Peroxidases / Q000737:chemistry*; D011485:Protein Binding / Q000502:physiology; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013059:Spectrum Analysis, Raman; D014026:Nicotiana / Q000201:enzymology*
chemical_list: D010544:Peroxidases