Tablet C, Hillebrand M. Theoretical and experimental study of the inclusion complexes of the 3-carboxy-5,6-benzocoumarinic acid with cyclodextrins.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008;
70:740-748. [PMID:
17954037 DOI:
10.1016/j.saa.2007.09.003]
[Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 09/04/2007] [Accepted: 09/13/2007] [Indexed: 05/25/2023]
Abstract
The 3-carboxy-5,6-benzocoumarinic acid (BzCum) presents important emission properties that could make it suitable to be used as a fluorescence marker for proteins. Since the guest-cyclodextrin interaction can be used as a model for the ligand-protein interaction, the host-guest complexes of BzCum with alpha-, beta-, gamma-, 2-hydroxypropyl-beta-cyclodextrin (2-HP-beta-CD) and 2-hydroxypropyl-gamma-cyclodextrin (2-HP-gamma-CD) were investigated by means of steady-state fluorescence measurements. As the guest may exist either in anionic or in neutral form, the experiments were performed at two different pH values, 9.48 and 2.11. The association constants and the stoichiometry of the complexes were estimated by non-linear regression analysis. A theoretical study of the complexes was made using molecular mechanics (MM) calculation methods. The electrostatic and van der Waals contributions to the energy were estimated and a discussion was made on this basis.
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