title: The artifactual nature of stavudine binding to human serum albumin. A fluorescence quenching and isothermal titration calorimetry study.
abstract: The interaction between stavudine, a nucleoside reverse transcriptase inhibitor and human serum albumin (HSA), was investigated by fluorescence quenching technique and isothermal titration calorimetry (ITC). A good linearity of albumin fluorescence quenching in the presence of stavudine was determined. Analyzing these data we obtained for the dissociation constant the value K(d)=(18.18 ± 0.46) × 10(-5)M. However, due to contradictory results obtained in ITC experiments, we checked the fluorescence quenching data for the inner-filter effect, the main confounding factor in the observed quenching. Based on the UV-vis absorption data we have corrected the observed fluorescence intensities and concluded, in accordance with ITC results, that stavudine binding to HSA is negligible and the observed quenching effect is entirely caused by a failure to correct for the inner-filter effect.
authors.affiliation: Department of Molecular and Biomolecular Physics, National Institute of Isotopic and Molecular Technologies, 400293 Cluj Napoca, Romania. silvia.neamtu@itim-cj.ro
authors.forename: Silvia
authors.initials: S
authors.lastname: Neamtu
authors.forename: Mihaela
authors.initials: M
authors.lastname: Mic
authors.forename: Mircea
authors.initials: M
authors.lastname: Bogdan
authors.forename: Ioan
authors.initials: I
authors.lastname: Turcu
mesh_terms: D002151:Calorimetry / Q000379:methods*; D005453:Fluorescence; D006801:Humans; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D018119:Stavudine / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D012709:Serum Albumin; D018119:Stavudine