A Kinetic Study on the Conformational Change of Bovine Serum Albumin Induced by Sodium Dodecyl Sulfate

Abstract

Abstract Stopped-flow measurements were made on the conformational change of bovine serum albumin induced by sodium dodecyl sulfate in a buffer solution containing 3.33 mmol/dm3 NaH2PO4 and 3.56 mmol/dm3 Na2HPO4 (pH 7.0, μ=0.014). The protein adopted a conformation with a smaller helical content than the original native state (helix to coil transition) upon the addition of the surfactant. The rate of transition depended strongly on the surfactant concentration. The results were compared with those of conformational changes of other proteins, in which a helical structure increased in the surfactant solution (coil to helix transition). It is noticeable that the value of the activation entropy is negative in the helix to coil transition, as compared with its positive and large values in the coil to helix transition. It seems that the binding of the surfactant to the protein causes the transition to only a particular conformation of the protein via each individual process.