Interactions between m-phenylenediamine and bovine serum albumin measured by spectroscopy

This study explored interactions between m-phenylenediamine (MPD) and bovine serum albumin (BSA) by spectrophotometry. The Stern-Volmer equation and UV-vis spectra examination at different temperatures and pH were used to explore different quenching mechanisms. Under simulated physiological conditions, the binding distance between MPD and BSA was 5.18 nm with a ratio of 1:1. The quenching effect of MPD on BSA intrinsic fluorescence depended strongly on pH, and maximum quenching was observed at alkaline pH. Moreover, the thermodynamic parameters of the MPD-BSA system showed that the predominant acting force between MPD and BSA was a hydrophobic force. The impact of MPD on the conformation of BSA and the effects of co-ions on binding interactions were also examined.