title: Spectroscopic investigations on the interaction between carbon nanotubes and catalase on molecular level.
abstract: The interactions between well-dispersed multiwalled carbon nanotubes (MWCNTs) and catalase (CAT) were investigated. The activity of CAT was inhibited with the addition of MWCNTs. After deducting the inner filter effect, the fluorescence spectra revealed that the tryptophan (Trp) residues were exposed and the fluorescence intensities of CAT increased with the increase in the MWCNTs concentration. At the same time, the environment of the Trp residues became more hydrophobic. The results of UV-vis absorption spectroscopy and CD spectra indicated that the secondary structure of CAT had been changed, and the amino acid residues were located in a more hydrophobic environment. Meanwhile, the UV-vis spectra indicated that the conformation of the heme porphyrin rings was changed. The microenvironment of CAT activity sites may be interfered by MWCNTs. This research showed that MWCNTs could not only contribute to the conformational changes of protein but also change the enzyme function.
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, Jinan, 250100, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Guan
authors.forename: Jingping
authors.initials: J
authors.lastname: Dai
authors.forename: Xingchen
authors.initials: X
authors.lastname: Zhao
authors.forename: Chunhua
authors.initials: C
authors.lastname: Liu
authors.forename: Canzhu
authors.initials: C
authors.lastname: Gao
authors.forename: Rutao
authors.initials: R
authors.lastname: Liu
mesh_terms: D001665:Binding Sites; D002374:Catalase / Q000037:antagonists & inhibitors / Q000737:chemistry; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D008856:Microscopy, Fluorescence; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D017433:Protein Structure, Secondary; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; D014364:Tryptophan; D002374:Catalase
keywords: Catalase; Enzyme Activity; Multiwalled Carbon Nanotubes; Spectrum Technology; Toxic Evaluation