Stabilization of proteins by solvents. Effect of pH and anions on the positive cooperativity of 2-nonanone binding to bovine serum albumin.

S Damodaran,J.E Kinsella

doi:10.1016/s0021-9258(18)43525-9

Abstract

The binding of 2-nonanone to bovine serum albumin exhibited positive cooperativity at low molal ratios of binding, indicating stabilization of the hydrophobic binding sites at low concentrations of 2-nonanone. The degree of cooperativity was affected by the type of anion present as evidenced from the changes in the Hill coefficient. The effectiveness of anions in increasing the Hill coefficient followed the Hofmeister series for anions, i.e. F- < SO42- < Cl- < Br- < SCN- < Cl3CCOO-. Also, the positive cooperativity decreased as the pH was increased from 3.0 to 7.0. The possible mechanism for the changes in the positive cooperativity of 2-nonanone binding to albumin in the presence of anions is discussed in terms of the stabilizing effect of ketones at low concentrations (Asakura, T., Adachi, K., and Schwartz, E. (1978) J. Biol. Chem. 253, 6423-6425) and the destabilizing effect of lyotropic anions on protein structure.

Highlights

Stabilization of Proteins by SolventsEFFECT OF pH A N D ANIONS ON THE POSITIVE COOPERATIVITY OF 2-NONANONE BINDING TO BOVINE SERUM ALBUMIN*
The binding of 2-nonanoneto bovine serum albumin interactions with small organic ligands (5) and its structural exhibited positive cooperativity atlow molal ratios of behavior at various pH values (6, 7) are understood
Anone binding to albumin in the presenceof anions is Distilled and deionized water was used in all the experiments

Summary

Stabilization of Proteins by Solvents

EFFECT OF pH A N D ANIONS ON THE POSITIVE COOPERATIVITY OF 2-NONANONE BINDING TO BOVINE SERUM ALBUMIN*. The binding of 2-nonanoneto bovine serum albumin interactions with small organic ligands (5) and its structural exhibited positive cooperativity atlow molal ratios of behavior at various pH values (6, 7) are understood. Binding,indicatingstabilization of thehydrophobic binding sites at low concentrationosf 2-nonanone.

EXPERIMENTAL PROCEDURES

Methods

RESULTS

The relationship between the partial molar entropy of the