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1

The DFT study on the electronic structure of boronic acid derivatives and its esters with fructose

Kur K., Kowalska-Baron A., Miller E.

Biotechnology and Food Science

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2018

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Vol. 82, nr 1

29--39

EN

Theoretical investigations are carried out to examine the geometrical structure and parameters of electron transitions to the lowest excited states of two boronic acid derivatives: 3-aminophenylboronic acid and 3-(acetamidomethyl)phenyl boronic acid and its cycling esters with fructose, using the DFT based 6-31 G(d,p) method. The most stable ester isomer of each acid has been selected. Predicted excitation wavelength are shorter (less than 0.5 eV) than experimental ones, what is in a good agreement considering limitations of the DFT method. In case of almost every calculated molecule the analysis of electronic transitions shows that transition S0→S1 involves electron transfer mainly from the HOMO to LUMO orbital.

2

Experimental and theoretical investigation of drotaverine binding to bovine serum albumin

Gałęcki K, Courtade G, McFall A., Prieschl Teixeira R., Grgic M., Esteve-Sistere M., Maglemose Westphalen R., Kowalska-Baron A.

Biotechnology and Food Science

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2013

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Vol. 77, nr 1

25--36

EN

This study was motivated by the need to provide more insight into the possible mechanism of the intermolecular interactions between antispasmodic drug drotaverine and one of the serum albumins (BSA), with the aim to indicate the most probable sites of these interactions. For this purpose both experimental (spectrofluorometric titration at various temperatures) and theoretical (molecular mechanics) methods have been applied. The obtained results clearly showed that drotaverine quenched BSA fluorescence, and the most probable mechanism is static quenching. The negative value of the theoretically predicted binding free Gibbs energy (-23.8 kJ/mol) confirmed the existence of the intermolecular interactions involving drotaverine and one tryptophan within BSA protein and was well agreed with the experimentally determined value of -25.2 kJ/mol.

3

The effect of immobilization in the PVA films on the fluorescence and phosphorescence lifetime of indole and its derivatives

Kowalska-Baron A., Choudhary P., Montes D.

Biotechnology and Food Science

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2011

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Vol. 75, nr 2

3-14

EN

This work is devoted to study how immobilization in the PVA films affects the fluorescence and phosphorescence lifetime of indole and its derivatives. The obtained results indicated that immobilization of the studied indoles in the PVA matrix, which leads to the increased microrigidity of the environment around the indole moiety, results in the increase of singlet and triplet excited state lifetime of the studied compounds. Most probably, the enhancement of the rigidity of the environment near the chromophore reduces the rates of the non-radiative deactivation pathways, which leads to the increase of excited state lifetimes of the studied compounds.

4

Ibuprofen-tyrosine (Val-Tyr, Val-Tyr-Val) interactions. Theoretical and experimental studies

Kowalska-Baron A., Brychtova M., Petrovic I., Passos Sene I., Quinones P., Sogorkova J.

Biotechnology and Food Science

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2011

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Vol. 75, nr 2

15-26

EN

In this work, the interactions between ibuprofen and tyrosine as well selected tyrosine-containing oligopeptides (Val-Tyr, Val-Tyr-Val) have been studied using both experimental (absorption and fluorescence spectroscopy) and theoretical (the PM3 method) techniques. The experimentally obtained values of association constant together with free Gibbs energy of association for the studied tyrosine-ibuprofen and Val- Tyr-; Val-Tyr-Val-ibuprofen complexes have been determined. The obtained results indicated that the mechanism of action of ibuprofen is most probably based on the hydrogen bonding interaction which involves hydroxyl group of tyrosine.