Protein–surfactant interactions. Nuclear magnetic resonance and binding isotherm studies of interactions between bovine serum albumin and sodium dodecyl sulphate

Abstract

The interactions between the protein, bovine serum albumin (BSA), and sodium dodecyl sulphate (SDS) at pH 5.6 have been studied by n.m.r. spectroscopy. The main findings are (i) above binding numbers of about 10–20, SDS molecules are in a micelle-like environment formed with apolar (and polar) groups of the protein, (ii) both the surfactant head groups and alkyl chains are associated with the protein at the initial ten binding sites, and (iii) when the protein is denatured by SDS much of the secondary and tertiary structure remains intact, including the initial binding sites.