Rendement quantique, temps de vie de fluorescence et heterogeneité des sites de fixation de la proflavine sur le DNA

✍ Scribed by G. Weill

• Publisher: Wiley (John Wiley & Sons)
• Year: 1965
• Tongue: English
• Weight: 317 KB
• Volume: 3
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1965.360030507

✦ Synopsis

The binding of Acridine Orange (AO) to DNA a t a phosphorus:dye molar ratio higher than 60 results in an increase of the quantum yield of fluorescence of the bound dye with respect to the free dye. The binding of proflavine (Pro) under the same conditions results, on the contrary, in a large decrease of quantum yield. This difference is surprising in view of the common increase of quantum yield of Acridine Orange and proflavine on going from aqueous to glycerol solution, the latter being a solvent with higher viscosity and lower dielectric constant. A comparative study of the spectra, lifetime of fluorescence 7, and quantum yield of fluorescence 4 of the free and bound dye can shed light on this specific interaction and discriminate between a uniform exaltation or quenching of the dye molecules and a heterogeneity in the binding sites. For AO, the ratio 7/47,,, where 70 is the "natural" lifetime calculated from absorption spectra, remains constant for free and bound dye, a test for uniform exaltation. For proflavine, T remains