PMID: 36383Jun 25, 1979

Influence of hydrogen and chloride ions on the interaction between sulfaethidole and bovine serum albumin studied by microcalorimetric and acid-base titrimetric methods

The Journal of Biological Chemistry
L H Janssen, T H Nelen

Abstract

From earlier studies it is known that bovine serum albumin has one high affinity binding site and several lower affinity sites for the sulfa drug N1-(5-ethyl-1,3,4-thiadiazol-2-yl)sulfanilamide (sulfaethidole) (Kostenbauder, H.B., Jawad, M.J., Perrin, J.H., and Averhart, V. (1971) J. Pharm. Sci. 60, 1658-1660). This binding has been further studied using equilibrium dialysis, microcalorimetry, and pH titration technique. Results of these studies show that the binding of sulfaethidole to the first (high affinity) site may be accompanied by an uptake of protons. Proton uptake is found to be zero at pH 7.4 and approximately 0.6 at pH 8.5 for each sulfaethidole molecule bound. The other binding sites for sulfaethidole are not proton linked. The first, and probably the other binding sites, are also Cl- ion linked; for example, the binding of sulfaethidole to the first binding site is accompanied by the displacement of (on average) one Cl- ion at pH 7.4 in 0.1 M NaCl. This explains the observation that the heat of binding of sulfaethidole to the high affinity site is -33.0 kJ.mol-1 in the absence of chloride ions, but only -22.8 kJ.mol-1 in the presence of 0.1 M Cl- (at pH 7.4).

Related Concepts

Chloride Ion Level
Sulfanilamide
Sulfanilamide, anti infective agent used to treat candida albicans, Homeopathic preparation
ALB
Uptake
Plasma Protein Binding Capacity
Calorimetry
Ligand Binding Domain
Sulfaethidole
Sulfonamide Anti-Infective Agents

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.