These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Study of steroid-proteininteractions by electron spin resonance spectroscopy. Binding of a spin-labelled dihydrotestosterone to bovine serum albumin.
    Author: Basset M, Defaye G, Chambaz EM.
    Journal: Biochim Biophys Acta; 1977 Apr 25; 491(2):434-46. PubMed ID: 192309.
    Abstract:
    The interaction of bovine serum albumin with dihydrotestosterone bearing a spin label at C-3 was studied using electron spin resonance (ESR) spectroscopy. Quantitative binding parameters (Ka approximately 10(5) M-1; maximum binding capacity; two sites/mol albumin) obtained by ESR were in good agreement with those given by equilibrium dialysis. ESR study at various temperatures allowed the calculation of the thermodynamic parameters of the steroid-protein interaction: deltaG=-6.8 kcal/mol; deltaH=-7.9 kcal/mol; deltaS=-3.2 cal/mol per degree and confirmed a transition temperature of about 65 degrees C for albumin. Na, Liland Ca salts had a generally favorable effect on the interaction whereas other ions (e.g. Hg, Cu) impaired the binding process. Study of the width of the ESR spectra of the protein-bound spin-labelled steroid and extrapolation of a 2 T value to infinite viscosity (Azz coupling constant) indicated a non-polar binding site, which became increasingly hydrophobic as the temperature was raised. Since this methodology can give both pertinent quantitative and qualitative data, ESR spectroscopy should be of value in the study of steroid-protein interactions of biological significance.
    [Abstract] [Full Text] [Related] [New Search]