Contrasting Thermodynamics Governs the Interaction of 3-Hydroxyflavone with the N-Isoform and B-Isoform of Human Serum Albumin
Herein we report the interaction of 3-hydroxyflavone (3HF) with various isomeric forms of Human Serum Albumin (HSA), namely, the N-isoform (or native HSA at pH 7.4) and the B-isoform (at pH 9.2). Spectroscopic signatures of 3HF reveal that the interaction of 3HF with the N-isoform of HSA results in...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 36(2020), 29 vom: 28. Juli, Seite 8570-8579 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2020
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Flavonoids Protein Isoforms Serum Albumin, Human ZIF514RVZR 3-hydroxyflavone ZTG9LSS5QH |
| Zusammenfassung: | Herein we report the interaction of 3-hydroxyflavone (3HF) with various isomeric forms of Human Serum Albumin (HSA), namely, the N-isoform (or native HSA at pH 7.4) and the B-isoform (at pH 9.2). Spectroscopic signatures of 3HF reveal that the interaction of 3HF with the N-isoform of HSA results in significant lowering of absorbance of the neutral species (λabs ∼ 345 nm) with concomitant increase of the anionic species (λabs ∼ 416 nm) whereas interaction with the B-isoform of HSA leads to selective enhancement of absorbance of the anionic species. The fluorescence profile of 3HF displays marked increase of intensity of the proton transferred tautomer (λem ∼ 538 nm) as well as the anionic species (λem ∼ 501 nm) for both the forms of the protein. However, analyses of the associated thermodynamics through temperature-dependent isothermal titration calorimetric (ITC) indicate that the interaction of 3HF with the N-isoform of HSA is more enthalpic in the lower temperature limit while the entropy contribution predominates in the higher temperature limit. Consequently, the 3HF-HSA (N-isoform at pH 7.4) interaction reveals an unusual thermodynamic signature of a positive heat capacity change (ΔCp = 3.84 kJ mol-1K-1) suggesting the instrumental role of hydrophobic hydration. On the contrary, the 3HF-HSA (B-isoform at pH 9.2) interaction shows qualitatively reverse effect. Consequently, the interaction is found to be characterized by an enthalpy-dominated hydrophobic effect (negative heat capacity change, ΔCp = -1.15 kJ mol-1K-1) which is rationalized on the basis of the nonclassical hydrophobic effect |
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| Beschreibung: | Date Completed 21.06.2021 Date Revised 21.06.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/acs.langmuir.0c01362 |