title: In vitro DNA binding studies of Aspartame, an artificial sweetener.
abstract: A number of small molecules bind directly and selectively to DNA, by inhibiting replication, transcription or topoisomerase activity. In this work the interaction of native calf thymus DNA (CT-DNA) with Aspartame (APM), an artificial sweeteners was studied at physiological pH. DNA binding study of APM is useful to understand APM-DNA interaction mechanism and to provide guidance for the application and design of new and safer artificial sweeteners. The interaction was investigated using spectrophotometric, spectrofluorometric competition experiment and circular dichroism (CD). Hypochromism and red shift are shown in UV absorption band of APM. A strong fluorescence quenching reaction of DNA to APM was observed and the binding constants (Kf) of DNA with APM and corresponding number of binding sites (n) were calculated at different temperatures. Thermodynamic parameters, enthalpy changes (ΔH) and entropy changes (ΔS) were calculated to be +181kJmol(-1) and +681Jmol(-1)K(-1) according to Van't Hoff equation, which indicated that reaction is predominantly entropically driven. Moreover, spectrofluorometric competition experiment and circular dichroism (CD) results are indicative of non-intercalative DNA binding nature of APM. We suggest that APM interacts with calf thymus DNA via groove binding mode with an intrinsic binding constant of 5×10(+4)M(-1).
authors: Faculty of Chemistry, Sensor and Biosensor Research Center (SBRC) & Nanoscience and Nanotechnology Research Center (NNRC), Razi University, P.O. Box 67149, Kermanshah, Islamic Republic of Iran. kashanian_s@yahoo.com
authors: Soheila
authors: S
authors: Kashanian
authors: Mohammad Mehdi
authors: MM
authors: Khodaei
authors: Fahimeh
authors: F
authors: Kheirdoosh
mesh_terms: D000818:Animals; D001218:Aspartame / Q000737:chemistry / Q000378:metabolism*; D001667:Binding, Competitive; D006690:Bisbenzimidazole / Q000378:metabolism; D002417:Cattle; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D007454:Iodides / Q000378:metabolism; D008751:Methylene Blue / Q000378:metabolism; D009994:Osmolar Concentration; D013057:Spectrum Analysis; D013549:Sweetening Agents / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D007454:Iodides; D013549:Sweetening Agents; D004247:DNA; D006690:Bisbenzimidazole; D008751:Methylene Blue; D001218:Aspartame