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Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis
Pangavhane, Sachin ; Böhm, S. ; Makrlík, E. ; Ruzza, P. ; Kašička, Václav
Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), cycl[-Val(1)-Pro(2)-Pro(3)-Ala(4)-Phe(5)-Phe(6)-Pro(7)-Pro(8)-Phe(9)-Phe(10)-], and sodium and potassium cations in methanol. Apparent stability constants of AA complexes with these alkali metal ions were determined from the dependence of effective mobility of AA on the concentration of these ions in the background electrolyte by the non-linear regression analysis. The AA complexes with Na+ and K+ ions were found to be relatively weak, with the apparent stability constants 343 L/mol and 35 L/mol, respectively.
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Determination binding constant of beta-blockers by capillary zone electrophoresis
Kanizsová, Lívia ; Zusková, Iva (advisor) ; Šteflová, Jana (referee)
Capillary zone electrophoresis identifies and determines various analytes based on their mobilities in a solution of the background electrolyte, which is exposed to an effect of the electric field. Besides that, it is a suitable method for determination of dissociation and complexation (stability) constants. In this paper the adrenergic β-blockers were chosen as analytes. β-blockers have at least one chiral center in the structure and separation of their enantiomers in presence of the chiral selectors by capillary electrophoresis is possible. For the enantioseparation, variously modified β-cyclodextrins are most often added to the background electrolyte. If the enantiomers of β-blockers have a different affinity to the chiral selector, they exhibit different effective mobilities. Based on a dependence of the effective mobility of analytes on the concentration of chiral selector, we are able to determine their stability constants. Key words: β-blockers, cyclodextrins, stability constant, capillary zone electrophoresis
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Study of DNA oligonucleotides interactions with ethidium bromide by partial-filling affinity capillary electrophoresis
Růžička, Martin ; Koval, Dušan ; Kašička, Václav
A partial filling affinity capillary electrophoresis was developed and applied to investigation of non-covalent molecular interactions between double stranded DNA oligonucleotide (Dickerson dodecamer) and classical DNA intercalator ligand –ethidium bromide (EtBr). Binding constants of DNA EtBr complexes were determined from the dependence of migration time changes of DNA oligomer (applied as analyte) on the length of ligand zones introduced beforehand as plugs of various lengths in hydroxypropylcellulose coated fused silica capillary. Binding constants of DNA-EtBr complex were found to be in the range 4.2 x 103 – 1.5 104 L/mol.
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