Study on the interaction of protein with Sulfonazo III by Rayleigh light scattering technique and its application

This is the first report on the determination of proteins with Sulfonazo II I by Rayleigh light scattering (RLS). At pH 4.23, the weak RLS of Sulfonazo III can be enhanced greatly by the addition of proteins, resulting in thre e characteristic peaks. Based on this, the reaction of Sulfonazo III and pr oteins was studied and a new method for quantation of proteins has been dev eloped. This method is very sensitive (0.30-30.5 mu g ml(-1) for bovine ser um albumen), rapid (<2 min), simple (one step), tolerance of most interferi ng substances, and gives a close value to that of Coomassie Brilliant Blue method in the determination of proteins in human serum. Mechanistic studies show that the RLS peaks correspond to the absorption valleys of the protei n-Sulfonazo III complex. (C) 1999 Elsevier Science B.V. All rights reserved .