Abstract: The interaction mechanism of metacycline (METC) and bovine serum albumin (BSA) was studied via fluorescence spectrometry and UV visible absorption spectrometry. The effects of temperature, pH, metal ions on the interaction of METC and BSA were studied. The results indicate that the mechanism of the i nteraction of METC with BSA belongs to static quenching. The major force of binding is static gravitation. Also, the distance of METC BSA was calculated via the Frster theory of nonradiation energy transfer. The mechanisms of interactions of metal complexes with BSA also belong to static quenching. The binding constants are different from the constant of the interaction between METC and BSA at room temperature, and the relevant binding sites are changed. It shows that the metal ions affect the structure and hydrophobicity of METC.

Key words: UVvisible absorption spectrum, fluorescence spectroscopy, bovine serum albumin, metacycline