Spermine as a porcine pancreatic elastase activator: spectroscopic and molecular simulation studies.

The aim of this study was to investigate the spermine effect on the thermal denaturation, conformation and activity of elastase at three temperatures of 303, 313 and 323 K in the Tris buffer, at pH 8.5, using UV-vis spectrophotometry, spectrofluorometry and circular dichroism as well as molecular docking and molecular simulation. The increased absorption of elastase in the presence of spermine suggested a change in the environment of tryptophan. It was found that under the influence of spermine, the emission intensity of elastase extremely was reduced, and the use of the Stern-Volmer equation showed that some static quenching had occurred. The thermodynamic parameters values (enthalpy and entropy) and the molecular docking technique also revealed that van der Waals forces or hydrogen bonding interactions played an important role in the binding process. The spermine-elastase complex formation led to increasing the value of the catalytic constant (