Binding of the Promen fluorescent probe to human serum albumin - A fluorescence spectroscopic study

The binding of Promen (6-propionyl-2-methoxynapthalene) to human serum albu min (HSA) was measured by fluorescence spectroscopy, finding only one class of binding sites on the protein. Hydrophobic interactions play an importan t role to stabilize the complex. Attempts were made to characterize its bin ding site using as competitors warfarin, phenylbutazone and diazepam, which bind in a specific site or region on the HSA. Fluorescence polarization me asurements and spectrofluorimetric results suggest that diazepam and Promen bind at different but interacting binding sites on the HSA. The changes in the fluorescence emission of the bound Promen in the presence of these dru gs, allow to use Promen to detect unspecific interactions with the site II on the HSA. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.