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Title:Enolase Dissociation Induced by High Pressure. A Study by Fluorescence Polarization
Author(s):Paladini, Alejandro Alberto
Department / Program:Physiology and Biophysics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biophysics, General
Abstract:Enolase is a protein of M.W. 90 kilodaltons, formed by two identical subunits of 45 kilodaltons each. Fluorescence polarization is the main spectroscopic property followed to characterize the dissociation of this enzyme under pressure.
In order to be able to measure this property under high pressure a cell was specially designed and constructed. The birefringency of the cell windows was determined to permit measurement of the true polarization changes of the biological system.
Experimental data using polarization of the intrinsic ultra violet fluorescence of the protein shows for enolase a change in volume upon dissociation of about -70 ml/mole. The free energy of dissociation measured at atmospheric pressure was about 9 kcal mole('-1), a value in close agreement with the literature. The polarization of the ultra violet fluorescence reflects mainly the increased freedom of rotation of tryptophan residues on dissociation.
Enolase was also labeled with dansylchloride and the polarization under pressure obtained. The values of the polarization in this case reflect mainly the volume of the particles.
Reversibility of the system measured in terms of polarization reproducibility after each pressure run is better than 98%. Theoretical analysis of the experimental data also allowed us to determine the decrease in volume upon dissociation at 1 atmosphere (-18 ml mole('-1)) and the compressibility of the residues at the boundary between the subunits (-36 ml mole('-1) kbar('-1)).
Issue Date:1980
Description:194 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
Other Identifier(s):(UMI)AAI8108620
Date Available in IDEALS:2014-12-14
Date Deposited:1980

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