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

Abstract

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