The Fluorescence Study of Interaction Between Bovine Serum Albumin and Polyacrylic Acid

Abstract

The complex formation of Bovine Serum Albumin (BSA) with anionic polyelectrolyte (polyacrylic acid, PAA) in aqueous solution was studied by a fluorescence technique, pH titration and HPLC analysis. The character of the interactions and solubility of the polycomplex particles depends on the BSA/PAA ratios and the pH of solution. The interaction at pH > pI (isoelectric point of BSA) (pH 6.0-7.0) is negligible weak and at pH 5.0 results with the formation of stable water-soluble polycomplexes at a wide range of protein/polymer ratios. The fluorescence intensity of BSA sharply decreased when an different amount of PAA was added and its maximum wavelength shifts towards the blue region. The protein molecules in the structure of soluble polycomplex particles are densely covered by the shelf of a polymer coil and practically "fenced off" from the water environment. This effect was reinforced by the increase of protein components. Existence of soluble and insoluble PAA-BSA complexes have been observed at pH < pI (pH 4.0-4.3). These soluble complexes characterized by the structure of particles in which protein molecules are densely covered by the shelf of a polymer coil. By the increase in the protein concentration, these complexes aggregate to an interpolymer species.

Cellular Response to Linear and Branched Poly(acrylic acid)

“…The effect of precipitated samples of 3‐arm star PNaA, hyperbranched PNaA, and linear PNaA in the shift of the emission maximum was found to be consistent with an investigation of the effect of PAA on the fluorescence properties of tryptophan residues in the protein from bovine serum albumin (BSA) . PAA reduced the fluorescence of tryptophan and shifted its emission maximum towards the blue region.…”

“…However, it should be noted that a similar merge of cellular lipids was observed in control groups subjected to the same conditions (Figure d and e); therefore, the merge may be a result of the serum deprivation and not directly due to the presence of PNaA. Nile Red has been previously shown to intensely fluoresce when combined with serum lipoproteins, especially for very low density lipoproteins which can cause a blue spectral shift . Starving L6 cells of serum appears to have resulted in a reduced concentration of serum lipoproteins and resulting in a lower spectral blue shift and hence the orange staining of lipid droplets.…”

“…Previous studies have found the interaction between bovine serum albumin (BSA) and PAA at pH 6–7 to be weak . BSA has an isoelectric point (p I ) of 4.9 .…”

Spectroscopic studies on the interaction between Pr(III) complex of an ofloxacin derivative and bovine serum albumin or DNA

“…Furthermore, DNA is an important cellular receptor, many chemicals exert their antitumor effects through binding to DNA thereby changing the replication of DNA and inhibiting the growth of the tumor cell, which is the basis of designing new and more efficient antitumor drugs and their effectiveness depends on the mode and affinity of the binding [5][6][7]. Therefore, this inspires considerable interest in the study of the biochemical behavior of some compounds including their interactions with serum proteins and DNA, which are primary target molecules, when metal compound is administered intravenously [8][9][10][11][12].…”