Document 0042
 DOCN  M9610042
 TI    A general, wide-rage spectrofluorometric method for measuring the
       site-specific affinities of drugs toward human serum albumin.
 DT    9601
 AU    Epps DE; Raub TJ; Kezdy FJ; Upjohn Laboratories, Kalamazoo, Michigan
       49001, USA.
 SO    Anal Biochem. 1995 May 20;227(2):342-50. Unique Identifier : AIDSLINE
       MED/96023416
 AB    Binding of drugs to serum albumin is one of the most important
       pharmacokinetic determinants and the design of drugs should take
       advantage of this property. In the present work, the fluorescent ligands
       Warfarin and dansylsulfonamide were used as probes of IIA site of human
       albumin and dansylsarcosine as the probe of the IIIA site. From the
       changes in fluorescence upon binding at 37 degrees C, pH 7.4, the
       following dissociation constants were determined: Warfarin, 3.43 +/-
       0.69 microM; dansylsulfonamide, 7.57 +/- 0.88 microM; and
       dansylsarcosine, 6.06 +/- 1.09 microM. Nonfluorescent ligands displace
       these probes competitively and the type of probe displaced identifies
       the site specificity of the ligands. Nonlinear least-squares analysis of
       the decrease in fluorescence accompanying the displacement yields the
       stoichiometry and the dissociation constant may also be estimated
       rapidly from displacement at a single competitor concentration. The
       method yields reliable Kd values for at least the range of 0.2 to 100
       microM. Representative dissociation constants for the IIA site-specific
       ligands are as follows: phenylbutazone, 1.9 +/- 0.3 microM; U-99,499,
       1.8 +/- 0.2 microM; U-96,988, 5.3 +/- 1.5 microM; and U-105,665, 42 +/-
       7 microM. For the IIIA site we find the following Kd values: oxazepam,
       27.7 +/- 2.1 microM; diazepam, 7.7 +/- 1.0 microM; and ibuprofen, 2.7
       +/- 1.2 microM. The method is eminently suitable for large-scale
       screening.
 DE    Binding Sites  Binding, Competitive  Dansyl
       Compounds/CHEMISTRY/*PHARMACOKINETICS  Fluorescent Dyes  Human  HIV
       Protease Inhibitors/CHEMISTRY/*PHARMACOKINETICS  Least-Squares Analysis
       Serum Albumin/*CHEMISTRY  Spectrometry, Fluorescence/*METHODS
       Warfarin/CHEMISTRY/*PHARMACOKINETICS  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).