The interactions between lipase and pyridinium ligands investigated by electrochemical and spectrophotometric methods

The interaction between pyridinium ligands derived from 4,4’-bipyridine (N,N’-bis(p-bromophenacyl)-4,4’-bipyridinium dibromide – Lr) and (N,N’-bis(p-bromophenacyl)-1,2-bis (4-pyridyl) ethane dibromide – Lm) with lipase enzyme was evaluated. The stability of the pyridinium ligands, having an essential role in biological systems, in 0.1 M KNO 3 as supporting electrolyte is influenced by the lipase concentration added. The pH and conductometry measurements in aqueous solution suggest a rapid ionic exchange process. The behavior of pyridinium ligands in the presence of lipase is investigated by cyclic voltammetry and UV/Vis spectroscopy, which indicated bindings and changes from the interaction between them. The voltammograms recorded on the glassy carbon electrode showed a more intense electronic transfer for the Lr interaction with lipase compared to Lm, which is due to the absence of mobile ethylene groups from Lr structure.