Complex formation between bovine serum albumin and poly(acrylic acid) as studied by viscometry, circular dichroism, and fluorescence spectroscopy

Abstract The complex formation between bovine serum albumin (BSA) and poly(acrylic acid) (PAA) in water was studied by viscosity measurements. It was found that at a BSA/PAA mole ratio of 233 the reduced viscosity of the solution shows a minimum, indicating that binding take place nonspecifically on the BSA surface. Circular dichroism (CD) spectra indicate that BSA does not suffer conformational alteration by the presence of PAA. Fluorescence spectroscopic studies were performed on 1‐anilinonaphthalene‐8‐sulfonate(ANS)‐BSA systems in presence of monocarboxylic acids or PAA. Again, in contrast to the hydrophobic binding of the monoacids, it was found that PAA binds to BSA nonspecifically on the surface.