title: Studies on the interaction of the food colorant tartrazine with double stranded deoxyribonucleic acid.
abstract: Interaction of the food additive tartrazine with double-stranded DNA was studied by spectroscopic and calorimetric techniques. Absorbance studies revealed that tartrazine exhibited hypochromism in the presence of DNA without any bathochromic effects. Minor groove displacement assay of DAPI and Hoechst 33258 suggested that tartrazine binds in the minor groove of DNA. The complexation was predominantly entropy driven with a smaller but favorable enthalpic contribution to the standard molar Gibbs energy. The equilibrium constant was evaluated to be (3.68 ± .08) × 10(4) M(-1) at 298.15 K. The negative standard molar heat capacity value along with an enthalpy-entropy compensation phenomenon proposed the involvement of dominant hydrophobic forces in the binding process. Tartrazine enhanced the thermal stability of DNA by 7.53 K under saturation conditions.
authors.affiliation: a Biophysical Chemistry Laboratory, Chemistry Division , CSIR-Indian Institute of Chemical Biology , Kolkata 700 032 , India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Basu
authors.affiliation: a Biophysical Chemistry Laboratory, Chemistry Division , CSIR-Indian Institute of Chemical Biology , Kolkata 700 032 , India.
authors.forename: Gopinatha
authors.initials: G
authors.lastname: Suresh Kumar
mesh_terms: D002152:Calorimetry, Differential Scanning; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D005505:Food Coloring Agents / Q000737:chemistry* / Q000378:metabolism; D057446:Hydrodynamics; D015394:Molecular Structure; D013057:Spectrum Analysis; D013645:Tartrazine / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D005505:Food Coloring Agents; D004247:DNA; D013645:Tartrazine
keywords: azo dye; calorimetry; minor groove binding; spectroscopy; tartrazine