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oai:www.ideals.illinois.edu:2142/23776 2023-07-10 col_2142_5131 col_2142_14828 com_2142_5130 com_2142_14827 com_2142_14793 com_2142_8903

Dynamics of oxygen penetration and diffusion into horse skeletal myoglobin revealed by quenching of zinc protoporphyrin IX fluorescence text Gratton, E. Carrero, Jenny 2011-05-07T14:26:39Z 2011-05-07T14:26:39Z 10000-01-01 1995 Oxygen quenching of tryptophan fluorescence in a number of globular proteins provided some of the early experimental evidence for conformational fluctuations in proteins. Gratton et al. (Biophysical J. 1984. 45:789-794) proposed a sequential two step model called the dynamic model for oxygen quenching of internally buried fluorophores in proteins. For this study, that model is utilized to analyze the dynamics associated with conformational fluctuations of oxygen entry into the protein and to obtain thermodynamic parameters associated with these fluctuations. We used zinc protoporphyrin IX reconstituted myoglobin and performed oxygen quenching experiments at different temperatures. The data was fit to the above model and k$\sp+$ (oxygen entry rate), k$\sp-$ (oxygen exit rate), and $\chi$ (oxygen migration rate) in horse skeletal myoglobin were obtained at each temperature. The activation energies were calculated using the value of k$\sp+$ and k$\sp-$ at each temperature. The protein-to-solvent partition coefficient for oxygen, $\alpha$, was also obtained at each temperature along with the thermodynamic variable, $\Delta$G, associated with this partition. The parameters k$\sp+$, k$\sp-$, $\chi$, and $\alpha$ have also been determined for the quenching of zinc protoporphyrin IX in 40% sucrose to assess the effect of viscosity on these parameters. The agreement of the steady state Stern-Volmer plot, calculated using the kinetic constants derived from the time resolved measurements with the experimental data, indicates that the dynamic model accurately represents the oxygen quenching process in horse skeletal myoglobin in all the temperature and viscosity range investigated. Made available in DSpace on 2011-05-07T14:26:39Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624300.pdf: 2681113 bytes, checksum: 082faa44db80bdc4fe7f6061c89d0ca0 (MD5) Previous issue date: 1995 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:06:46Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:32:04-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9624300 (UMI)AAI9624300 http://hdl.handle.net/2142/23776 eng Copyright 1995 Carrero, Jenny Biology, Animal Physiology Biophysics, General Biology, Animal Physiology Biophysics, General Biology, Animal Physiology Biophysics, General University of Illinois at Urbana-Champaign Dissertation Ph.D.