Spectroscopic studies on the interactions between 3,4-dihydropyrimidin-2(1H)-ones and bovine serum albumin

The interactions between 3,4-dihydropyrimidin-2(1H)-ones (DHPM) and bovine serum albumin (BSA) were investigated by fluorescence and ultraviolet spectroscopy under imitated physiological conditions. The experimental results showed that all DHPM could form complexes with BSA. Static quenching and non-radiation energy transfer are the main reasons leading to the fluorescence quenching. The binding constants (KA) and the number of binding sites (n) were calculated. According to Förster theory of non-radiation energy transfer, the binding distances (r) between BSA and DHPM are less than 7 nm. The relationship between different aryl groups in pyrimidine ring and the binding ability of DHPM with BSA is preliminarily discussed. Moreover, the synchronous fluorescence spectra indicated that the conformation of BSA has not been changed.