C. Castelain et C. Genot, CONFORMATIONAL-CHANGES OF BOVINE SERUM-ALBUMIN UPON ITS ADSORPTION INDODECANE-IN-WATER EMULSIONS AS REVEALED BY FRONT-FACE STEADY-STATE FLUORESCENCE, Biochimica et biophysica acta (G). General subjects, 1199(1), 1994, pp. 59-64
Front-face fluorescence spectroscopy was used to characterise dodecane
-in-buffer (0.1 M phosphate buffer, pH = 7.6) emulsions stabilised by
bovine serum albumin (BSA). A 15-nm blue-shift of the emission maximum
of the adsorbed protein and a significant increase of its fluorescenc
e quantum yield were observed. The contribution of tyrosyl residues to
total fluorescence was tentatilely evaluated from difference spectra
and an R ratio taking into account the stray-light interference; R inc
reased upon BSA adsorption but the Tyrosine contribution remained weak
in all cases. Thus, conformational changes of the protein take place
upon BSA adsorption onto the dodecane-water interface. They involve mo
difications in the environment of the protein aromatic amino acids esp
ecially of the tryptophanyl residues which are displaced to a more hyd
rophobic location. Moreover, the proportions of adsorbed and non-adsor
bed BSA in emulsions can be estimated from the position of the emissio
n maximum.