Chiral analysis of β‐alanyl‐d,l‐tyrosine and its derivatives and estimation of binding constants of their complexes with 2‐hydroxypropyl‐β‐cyclodextrin by capillary electrophoresis

Abstract

Chiral CE methods were developed for the elucidation of l-or d-configuration of tyrosine residue in antimicrobial dipeptide β-alanyl-tyrosine (β-Ala-Tyr) isolated from the hemolymph of larvae of fleshfly Neobellieria bullata and for the evaluation of enantiopurity of its synthetic isomers (β-Ala-d-Tyr and β-Ala-l-Tyr), and enantiomers of their amidated and acetylated derivatives, β-Ala-d,l-Tyr-NH 2 and N-Ac-β-Ala-d,l-Tyr, respectively. Baseline separations were achieved for all three pairs of enantiomers: (i) for β-Ala-d,l-Tyr in acidic background electrolyte composed of 32/50 mM tris(hydroxymethyl)aminomethane/H 3 PO 4 , pH 2.5, and 20 mg/mL 2-hydroxypropyl-β-cyclodextrin as chiral selector; (ii) for β-Ala-d,l-Tyr-NH 2 enantiomers in acidic background electrolyte consisting of 48/50 mM tris(hydroxymethyl)aminomethane/H 3 PO 4 , pH 3.5, and 30 mg/mL 2hydroxypropyl-β-cyclodextrin; and (iii) for enantiomers of N-Ac-β-Ala-d,l-Tyr in alkaline background electrolyte composed of 50/49 mM Na 2 B 4 O 7 /NaOH, pH 10.5, and 60 mg/mL 2-hydroxypropyl-β-cyclodextrin. From CE analyses of mixed samples of isolated β-Ala-Tyr and synthetic standards β-Ala-l-Tyr and β-Ala-d-Tyr, it turned out that isolated β-Ala-Tyr was pure l-enantiomer. In addition, the average apparent binding constants, K b , and average actual ionic mobilities of the complexes of β-Ala-d,l-Tyr and its above derivatives with 2-hydroxypropylβ-cyclodextrin were determined. These complexes were weak, with K b values ranging from 11.2 to 79.1 L/mol. Their cationic mobilities were equal to (5.6-9.2) × 10 -9 m 2 /V/s, and anionic mobilities to (-1.3-1.6) × 10 -9 m 2 /V/s.

Recent developments in capillary and microchip electroseparations of peptides (2021–mid‐2023)

“…2‐Hydroxypropyl‐β‐cyclodextrin (2‐HP‐β‐CD) was found as a suitable stereoselector for chiral CE analysis of antimicrobial dipeptide β‐Ala‐Tyr isolated from the hemolymph of the fleshfly Neobellieria bullata and its synthetic amidated (β‐Ala‐ d , l ‐Tyr‐NH 2 ) and acetylated (N‐Ac‐β‐Ala‐ d , l ‐Tyr) derivatives [279]. The baseline enantioseparation was obtained for all three pairs of enantiomers, see Figure 9.…”

“…2-Hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was found as a suitable stereoselector for chiral CE analysis of antimicrobial dipeptide β-Ala-Tyr isolated from the hemolymph of the fleshfly Neobellieria bullata and its synthetic amidated (β-Ala-d,l-Tyr-NH 2 ) and acetylated (N-Ac-β-Ala-d,l-Tyr) derivatives [279]. The baseline enantioseparation was obtained for all three pairs of enantiomers, see Figure 9 The effect of chiral ionic liquids composed of tetraalkylammonium ions and the AAs (Asn, Asp, and Pro) on the CD-mediated CE enantioseparations of dipeptides Ala-Phe, Ala-Tyr, and Phe was studied by Konjaria and Scriba [280].…”

Development and evaluation of a novel fluorescent chiral derivatization reagent DBD-S-M-Pro: first observation of four chiral amino acids in human hair

“…Current chiral separation and detection techniques include high-performance liquid chromatography (HPLC), 7 gas chromatography (GC), 8 and capillary electrophoresis (CE). 9 However, the derivatization process of GC analysis requires acidic conditions and high-temperature detection. 10 Perfluorinated acylation reactions can lead to the racemization of amino acids, which lowers the quantification accuracy.…”

β‐Cyclodextrin and folic acid host–guest interaction binding parameters determined by Taylor dispersion analysis and affinity capillary electrophoresis

“…Recently, capillary electrophoresis (CE), a free solution-based approach, has shown significant potential as an alternative method for studying binding interactions [27][28][29][30]. With low sample consumption, fast analysis speed, and high separation efficiency, affinity capillary electrophoresis (ACE) [31,32] has been used to study noncovalent interactions involving biological molecules with no need for the immobilization of protein or ligand molecules [33][34][35].…”