EFFECTS THAT ENVIRONMENT EXERTS ON SPECTROSCOPIC PROPERTIES OF CERTAIN DYES THAT ARE BOUND BY BOVINE SERUM ALBUMIN

Experiments are reported in which the polarity of the dye binding sites of bovine serum albumin was estimated by changes in the spectroscopic properties of 1-anilinonaphthalene-8-sulphonic acid, 1-dimethylaminonaphthalene-5-sulphonic acid, Rhodamine B and Phenol Blue. The polarity indicated by the first two dyes was less than that indicated by the second pair. Experiments are reported that show all the dyes are bound to the same protein sites and an explanation of the discrepancy is suggested based on the demonstration that the spectroscopic properties of the naphthalene sulphonic acids depend not only on the polarity of the solvent but also on its rigidity and its ability to solvate the dye. © 1969.