Study on the interaction between florasulam and bovine serum albumin

• Published in: Journal of fluorescence Vol. 17; no. 6; pp. 721 - 726
• Main Authors: Ran, Dehuan, Wu, Xia, Zheng, Jinhua, Yang, Jinghe, Zhou, Haiping, Zhang, Meifeng, Tang, Yongjun
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.11.2007
• Subjects: Animals; Atomic structure; Binding Sites; Cattle; Circular Dichroism; Dichroism; Energy Transfer; Enthalpy; Fluorescence; Hydrogen bonds; In Vitro Techniques; Protein Conformation; Pyrimidines - chemistry; Pyrimidines - metabolism; Quenching; Serum albumin; Serum Albumin, Bovine - chemistry; Serum Albumin, Bovine - metabolism; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Sulfonamides - chemistry; Sulfonamides - metabolism; Thermodynamics; Tryptophan - chemistry; Ultraviolet absorption; Van der Waals forces
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-007-0226-9

In this paper, the interaction between florasulam (FU, 2',6',8-trifluoro-5-methoxy [Kragh-Hansen U, Molecular aspects of ligand binding to serum albumin. Pharmacol Rev 33(1):17-53 1981; Carter DC and Ho JX, Structure of serum albumin. Adv Protein Chem 45:153-203 1994; He XM, and Carter DC, Atomic structure and chemistry of human serum albumin. Nature 358(6383):209-215 1992] triazolo [1,5-c]pyrimidine-2-sulfonanilide) and bovine serum albumin (BSA) was investigated by fluorescence, ultraviolet absorption (UV) and Far-UV circular dichroism (CD) spectrometries. A strong fluorescence quenching was observed and the quenching mechanism was considered as static quenching. The binding constant of FU with BSA at 299 and 309 K were obtained as 1.5 x 10(4) and 7.1 x 10(3) l mol(-1), respectively. There was one binding site between FU and BSA. The thermodynamic parameters enthalpy change (DeltaH) and entropy change (DeltaS) were calculated as -57.89 kJ mol(-1) and -113.6 J mol(-1) K(-1), respectively, which indicated that the acting force between FU and BSA was mainly hydrogen bond and Van der Waals force. According to the Förster non-radiation energy transfer theory, the average binding distance between donor (BSA) and acceptor (FU) was obtained (r = 1.59 nm). The investigations of the UV/Vis and CD spectra of the system showed that the conformation of BSA was changed in presence of FU.