[Study on the ternary complex of FLRX, zinc(II) and BSA by the method of fluorescence]

The influences of fleroxacin (FLRX) on the fluorescence of bovine serum albumin(BSA), zinc(II) on that of bovine serum albumin, and zinc(II) on the of fleroxacin and bovine serum albumin were studied under imitated the physiological condition. It was shown that both fleroxacin and zinc(II) have a powerful ability to quench the BSA fluorescence via a nonradiative energy transfer mechanism. But the fluorescence quenching action of fleroxacin on BSA was much stronger in the presence of zinc (II). The fluorescence quenching data were analyzed according to Stern-Volmer equation and double-reciprocal equation, and the binding constant(K) and the binding sites(n) were obtained. In the system of binary complex of FLRX and BSA, K = 5.44 x 10(4) and n = 1.05, while in the system of binary complex of zinc(II) and BSA, K = 2.19 x 10(9) and n = 2.