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Updated: Apr 1, 2026

Quantifying the Binding Interactions Between CuII and Peptide Residues in the Presence and Absence of Chromophores
Published on: April 5, 2022
Determination of the kinetics underlying the pKa shift for the 2-aminoanthracenium cation binding with
Suma S Thomas1, Cornelia Bohne1
1Department of Chemistry, University of Victoria, PO Box 3065, Victoria, BC V8W 3V6, Canada. cornelia.bohne@gmail.com.
Abstract:
The binding dynamics of the 2-aminoanthracenium cation (AH(+)) and 2-aminoanthracene (A) with cucurbit[7]uril (CB[7]) was studied using stopped-flow experiments. The kinetics was followed by measuring the fluorescence changes over time for AH(+) and A, which emit at different wavelengths. The studies at various pH values showed different mechanisms for the formation of the AH(+)@CB[7] complex, with this complex formed either by the binding of AH(+) or by the initial binding of A followed by protonation. In the latter case, it was possible to determine the protonation ((1.5 ± 0.4) × 10(9) M(-1) s(-1)) and deprotonation (89 ± 7 s(-1)) rate constants for complexed A/AH(+), which showed that the pKa shift of +3.1 for A/AH(+) in the complex is mainly due to a lower deprotonation rate constant.
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