Circular dichroic investigations into binding of sulfonamides to serum albumin
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The binding of twelve structurally related sulfonamides to serum albumins including human was investigated using a circular dichroic technique. Some differences of circular dichroic spectral characteristics were observed when sulfonamides were bound to the same albumin or when the drug was bound to several albumins. The differences in these circular dichroic characteristics may be due to various asymmetries. The Scatchard plots indicated that only the primary site was capable of inducing ellipticities of the drugs. The interaction with rabbit serum albumin showed significantly large binding constants and apparent anisotropy factors (g′, values), in comparison with other albumins. No significant correlation between the g′ values of the induced circular dichroic bands and partition coefficients or/and pKa values was observed. The induced ellipticities of the drug-albumin complexes decreased with pH. This pH dependence can be explained by the ionization of drug and albumin as well as the conformational change of the albumin.
KeywordsBinding sites Circular dichroism Serum albumin Sulfonamides
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- 1.Anton AH. A drug-induced change in the distribution and renal excretion of sulfonamides. J Pharm Exp Ther 1961;134:291–303.Google Scholar
- 2.McQueen EG. Comparison of tissue fluid and plasma concentrations of a protein-bound drug sulphormethoxine byin vivo dialysis in rats. Br J Pharm Chemother 1968;33:312–8.Google Scholar
- 3.Anton AH. The effect of disease, drugs and dilution on the binding of sulfonamides in human plasma. Clin Pharm Ther 1968;9:561–7.Google Scholar
- 8.Nakamura H, Imamura Y, Umeda T, Otagiri M. Effect of phenylbutazone on serum protein binding and disposition of sulfadimethoxine in human and rabbit. Xenobiotica Metab Dispos 1988;3:417–24.Google Scholar
- 10.Müller WE, Wollert U. Circular dichroism studies on the interaction of four structurally related long-acting sulfonamides with human and bovine serum albumin. Biochem Pharmacol 1976;35:1459–64.Google Scholar
- 13.Schellman JA. Symmetry rules for optical rotation. Acc Chem Res 1968;1:144–51.Google Scholar
- 14.Tanford C, Swanson SA, Shore WS. Hydrogen ion equilibria of bovine serum albumin. J Am Chem Soc 1955;77:6414–21.Google Scholar
- 15.Parsons DL, Vallner JJ. A new method for the determination of the site binding constant of each species of a partially ionized drug. Acta Pharm Suec 1980;17:13–30.Google Scholar