Ascorbic Acid and BSA Protein in Solution and Films: Interaction and Surface Morphological Structure

Abstract

This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, K, determined for aggregates from BSA and AA was found to be about 102 M−1, which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state.

The Influence of Arginine on the Response of Enamel Matrix Derivative (EMD) Proteins to Thermal Stress: Towards Improving the Stability of EMD-Based Products

“…Fig 5 shows second derivative FT-IR spectra from the dried EMD-buffer solutions (cf. the images in Figs 1 and 3 ) in the wavenumber range corresponding to the amide I band, suggesting primarily mixed β-sheet and β-turn structure [ 45 ]. Thus, spectra obtained from the specimens prepared at pH 2 ( Fig 5(a) ), an intramolecular β-sheet peak was visible at 1633 cm -1 and the peaks at 1660, 1668 and 1675 cm -1 were assigned to β-turns.…”

“…The peak at 1683 was associated with β-turns/intermolecular β-sheets and there was a further intermolecular β-sheet peak at 1698 cm -1 . The peaks at 1643 and 1652 cm -1 were assigned to random coils and random coils/α-helices, respectively, and the peak at 1620 cm -1 was tentatively identified with polyproline II helix structure, based on previous observations of aqueous amelogenin at different pH [ 12 , 45 ].…”

Morphological Analysis and Interaction of Chlorophyll and BSA

“…The UV-Vis spectroscopy technique is a simple and effective method to investigate the molecular interaction and complex formation [ 21 ]. UV-Vis analyses were performed for BSA in solution with physiological pH and concentration of 1.9 × 10 −6 mol·L −1 (required for better visualization of the band at 278 nm) and modified solution after the addition of Chl at different concentrations.…”

“…A lot of studies on interaction of BSA and ligands have been carried out. In these works, compounds including 2-(4-N,N-dimethylamino) phenylimidazo [4,5-b]pyridine (DMAPIP-b) [ 10 ], imidazolium chloride ionic liquids [ 11 ], prednisolone [ 12 ], aspirin [ 13 ], resveratrol [ 14 ], genistein [ 14 ], curcumin [ 14 – 16 ], malachite Green [ 17 ], bright red 6C [ 18 ], anticancer drugs [ 19 ], heparin [ 20 ], and ascorbic acid [ 21 ] were used. In particular, the behavior of the binding of chlorophyll (Chl) to BSA has been also examined [ 22 ] because it has been shown that this ligand can exhibit antimutagenic property against several potential human carcinogens [ 23 , 24 ], action antioxidant [ 25 ], and antigenotoxic [ 26 ].…”

“…Chl can bind to biological proteins modulating their activities. This bind process is determined by the behavior of interactions between drugs with proteins [ 21 ]. To the best of our knowledge, there have been no studies on interaction between Chl and proteins in casting films.…”