Hamadan University of Medical Sciences Avicenna Journal of Medical Biochemistry 2345-4113 10 2 2022 12 21 Interaction of 3-(1H-tetrazol-5-yl) Coumarin With Bovine Serum Albumin and Calf Thymus DNA: Deciphering the Mode of Binding by In Vitro Studies 153 161 10.34172/ajmb.2022.2374 EN Javad Sargolzaei https://orcid.org/0000-0001-5366-2014 Soheila Khaghaninejad Sogol Meknatkhah Journal Article 10.34172/ajmb.2022.2374 2022 07 16 2022 09 18 Background: Coumarins comprise a large family of heterocyclic compounds with a benzo-a-pyrone moiety. Objectives: This study aimed to analyze the binding affinity of 3-(1H-tetrazol-5-yl) coumarin to bovine serum albumin (BSA) and calf thymus DNA (Ct-DNA) using fluorescence spectroscopy. The quenching of fluorescence was recognized during the interaction between 3-(1H-tetrazol-5-yl) coumarin and BSA, followed by a static mechanism. Methods: The hydrogen bonds, hydrophobic interactions, and Vander Waals forces were regarded as the principal part in the 3-(1H-tetrazol-5-yl) coumarin and BSA complexation process. The fluorescence spectral characteristics demonstrated an enhancement in fluorescence intensity of the 3-(1H-tetrazol-5-yl) coumarin in the presence of ct-DNA solution. Results: The experimental results indicated that the 3-(1H-tetrazol-5-yl) coumarin binds to DNA via interjection, hydrogen bonds, and Vander Waals forces. This work illustrated that BSA fluorescence was quenched by 3-(1H-tetrazol-5-yl) coumarin via a static mechanism and the ct-DNA fluorescence enhancement by 3-(1H-tetrazol-5-yl) coumarin was a static process. The secondary structure of proteins changed upon drug binding. Conclusion: It is deduced that 3-(1H-tetrazol-5-yl) coumarin represents a higher binding affinity to DNA compared to BSA. This finding can be useful in designing more effective new drugs with fewer side effects.