Influence of the separation of the charged groups and aromatic ring on interaction of tyrosine and phenylalanine analogues and derivatives with β-cyclodextrin

Investigating the inclusion properties of aromatic amino acids complexing beta-cyclodextrins in model peptides

“…Hydration and solubility of proteins and, as a consequence, their stability and activity, can significantly change by modulating the surrounding solutes and solvent molecules, e.g., via the formation of inclusion complexes (Aachmann et al 2012;Ekka and Roy 2013;Iacovino et al 2013;Loftsson and Brewster 1996;Mrozek et al 2005). However, due to the high conformational complexity of the three-dimensional structure of a protein, direct characterization of the solute-solvent influence on biological macromolecules is still very challenging.…”

Influence of the substituent on amide nitrogen atom of N-acetyl tyrosine on interactions with β-cyclodextrin

“…In the presence of b-cyclodextrin the absorption spectra of the studied compounds shift to the longer wavelengths for a few nanometres comparing to that in pure water. Moreover, a small red shift of the emission spectra (about 1 nm) as in the case of tyrosine itself as well as its analogues and derivatives [5,14,16] is observed. Furthermore, an increase of the fluorescence intensity of the emission band was observed as a result of addition of b-CD to water solution of tyrosine derivatives.…”

“…3 fluorescence intensity decays of N-AcTyr(Pr n ) 2 in water at different b-CD concentrations are presented. Moreover, the fluorescence intensity decays of N-acetyltyrosine and its amides studied without [14] and with cyclodextrin are heterogeneous (two exponents are needed for correct describing of the fluorescence intensity decay, Tables 2 and 3). The higher the cyclodextrin concentration, the higher both fluorescence lifetimes are, while pre-exponential factors show irregular changes.…”

“…Apart from the fluorescence intensity (fluorescence quantum yield) other photophysical properties proportional to the concentration of the free and bound guest molecule can be used for stoichiometry and binding constant calculation [5,6,14,48,53,54]. For two components system, normalized pre-exponential factors of the fluorescence lifetime (a) for all forms present in the solution obtained from the global analysis of the fluorescence intensity decays as well as the average fluorescence lifetime defined by Eq.…”

“…They are widely used in different technological processes [3,4]. Aromatic amino acids [5][6][7][8][9][10][11][12][13][14] and peptides [15][16][17][18][19][20][21] are one group of compounds whose interactions with cyclodextrins have been extensively studied because of their feature similar to enzyme-substrate complexes. Complexation reactions involving cyclodextrins are also highly important to drug delivery system technology [22][23][24].…”