Use of Viscosity to Probe the Interaction of Anionic Surfactantswith a Coagulant Protein from Moringa oleifera Seeds

摘要

The intrinsic viscosity of the coagulant protein was evaluated from the flow times of the protein solutions through a capillaryviscometer, and the results suggested the coagulant protein to be globular. The interactions of the coagulant protein with anionicsurfactant sodium dodecyl sulphate (SDS) and sodium dodecyl benzene sulfonate (SDBS) were also investigated by capillaryviscometry. We conclude that there is strong protein-surfactant interaction at very low surfactant concentrations, and the behaviorof the anionic surfactants in solutions containing coagulant protein is very similar. The viscometry results of protein-SDS systemare compared with surface tension, fluorescence, and circular dichroism reported earlier. Combining the results of the four studies,the four approaches seem to confirm the same picture of the coagulant protein-SDS interaction. All the physical quantities whenstudied as function of surfactant concentration for 0.05% (w/v) protein solution either exhibited a maximum or minimum at acritical SDS concentration.