Intra-albumin migration of bound fatty acid probed by spin label ESR.
Conventional ESR spectra of 16-doxyl-stearic acid bound to bovine and human serum albumin were recorded at different temperatures in order to investigate the status of spin-labeled fatty acid in the interior of the protein globule. A computer spectrum simulation of measured spectra, performed by non-linear least-squares fits, clearly showed two components corresponding to strongly and weakly immobilized fatty acid molecules. The two-component model was verified on spectra measured at different pH. Thermodynamic parameters of the spin probe exchange between two spin probe states were analyzed. It was concluded that at physiological conditions, fatty acid molecules permanently migrate in the globule interior between the specific binding sites and a space among albumin domains.
Gurachevsky
Andrey
A
Department of Research and Development, MedInnovation GmbH, Berlin 13599, Germany. a.gurachevsky@medinnovation.de
Shimanovitch
Ekaterina
E
Gurachevskaya
Tatjana
T
Muravsky
Vladimir
V
D000418:Albumins / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005227:Fatty Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D015335:Molecular Probes; D013113:Spin Labels; D013816:Thermodynamics
D000418:Albumins; D005227:Fatty Acids; D015335:Molecular Probes; D013113:Spin Labels