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

• Published in: Journal of separation science Vol. 45; no. 17; pp. 3328 - 3338
• Main Authors: Sázelová, Petra, Šolínová, Veronika, Schimperková, Tereza, Jiráček, Jiří, Kašička, Václav
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.09.2022
• Subjects: 2‐hydroxypropyl‐β‐cyclodextrin; Antiinfectives and antibacterials; Binding; Binding constant; capillary electrophoresis; chiral separation; Cyclodextrins; dipeptides; Electrolytes; Electrophoresis; Enantiomers; enantioseparation; hemolymph; Larvae; Sarcophaga bullata; separation; Tyrosine; β‐alanyl‐tyrosine; enantioseparation; 2-hydroxypropyl-β-cyclodextrin; chiral separation; capillary electrophoresis; Binding constant; β-alanyl-tyrosine
• ISSN: 1615-9306; 1615-9314; 1615-9314
• DOI: 10.1002/jssc.202200158

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‐NH2 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/H3PO4, pH 2.5, and 20 mg/mL 2‐hydroxypropyl‐β‐cyclodextrin as chiral selector; (ii) for β‐Ala‐d,l‐Tyr‐NH2 enantiomers in acidic background electrolyte consisting of 48/50 mM tris(hydroxymethyl)aminomethane/H3PO4, pH 3.5, and 30 mg/mL 2‐hydroxypropyl‐β‐cyclodextrin; and (iii) for enantiomers of N‐Ac‐β‐Ala‐d,l‐Tyr in alkaline background electrolyte composed of 50/49 mM Na2B4O7/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, Kb, and average actual ionic mobilities of the complexes of β‐Ala‐d,l‐Tyr and its above derivatives with 2‐hydroxypropyl‐β‐cyclodextrin were determined. These complexes were weak, with Kb values ranging from 11.2 to 79.1 L/mol. Their cationic mobilities were equal to (5.6–9.2) × 10–9 m2/V/s, and anionic mobilities to (‐1.3–1.6) × 10–9 m2/V/s.