CIRCULAR DICHROISM SPECTRA OF COMPLEXES OF 1-ANILINO-8-NAPHTHALENESULFONATE WITH BOVINE SERUM ALBUMIN . EVIDENCE FOR HETEROGENEITY OF BINDING

The adsorption of 1-anilino-8-naphthalenesulfonate by bovine serum albumin induces asymmetry in the ligand molecule. The sign and magnitude of the resulting circular dichroic bands vary with the average degree of saturation of the protein with ligand. Matrix rank analysis of the data demonstrates two spectrally distinguishable components within the set of five primary binding sites. The accurate differential measurements obtained in circular dichroism reflect heterogeneity undetectable in direct determinations of protein-ligand equilibria. © 1969, American Chemical Society. All rights reserved.