Interaction of Pyrene with Human Serum Albumin (HSA): A Ilv-Vis Spectroscopy Study

In this research the interaction of Pyrene (Cullm) as a polycyclic aromatic hydrocarbon with human serumalbumin (HSA) has been investigated. Variations of UV-Vis spectrum of Prene can help us to investigatethe changes that are ereated in protein structure. Pyrene in insoluble in water and soluble in acetic acid.mixture of acetic acid and water and in organic solvents such as methanol. UV-Vis spectrum of Pyrene hasthree strong bands at 308,349 and 433 on'. A series of UV-Vis titration experiments were earned out basedon titration of a given amount of Pyrene with ESA at various pH. phosphate buffer and differenttemperatures. 1 he titration spectrum were analyzed at each temperature using SQUAD program and basedon 1:1, I:2 and 2:1 models. Results indicated that formed complex between Pyrene and ESA is I:I. Allthermodynamic parameters of complex formation including AG", AH', AS' and formation constant ofcomplex (K) were calculated and results showed that the process is endothermic and entropy driven. Thisissue shows the predornmant role of hydrophobic forces in inleraction between Pyrene and ESA.Investigating the effect of increasing the ionic strength on absorption spn, ram of Pyrene-HSA complexalso confirms the results of thermodynamic studies. Using the changes in the structure of absorptionspectrum of Pyrene in water. plasma of human blood and in a buffer solution of ESA, we could indicatethat Pyrene in Mood plasma is concentrated in hydmphilic micro phases of plasma proteins and lipid.