Transmembrane Distribution Of PAHs And Toxicity Mechanism

Lecithin liposome was used as simulation membrane to investigate the interactions of PAHs including anthracene, phenanthrene and membrane. Results reveal this interaction obeys the Nerst partition law. The partition coefficients of anthracene and phenanthrene were calculated and their binding bonds in liposomes were clarified. K_m/wof phenanthrene is 800, and K_m/w of anthracene is 1240. Effects of electrolyte, temperature, acidity of solution were analyzed; the effect of the molecular structure was discussed in detail, too. The effect of ion intensity mainly was because the ion intensity influence the gathering number of Lecithin liposome micelle, the temperature influence also was ties through influence the gathering number of Lecithin liposome micelle, the pH value influence is affects through affects the electric charge. Effects of protein, amino acid and saccharide were also analyzed; the effect of the molecular structure also was discussed in detail. The effect of protein, amino acid and saccharide were smaller, the drainage of amino acid affect through steric hindrance, the saccharide have thesteric effect through the hydroxyl function. Besides, the inverse partition of apolar compounds from liposome to an analogue cytosol was first proposed. K_m/w of phenanthrene is 221, and K_m/w of anthracene is 1804.The experiments with live E. coli confirmed the in-vitro result, i.e. apolar compounds penetrated the membrane phospholipid bilayer and entered cytosol. The Transmembrane Impedance Effect (TIE) was advanced and it will provide a very helpful experimental strategy for toxicity assessment of a lipophilic compound. Results reveal that the interaction between anthracene, phenanthrene and real cell membrane obeys the Nerst partition law, thus obtains the of phenanthrene and anthracene distribution coefficient was 611 and 2,070. Anthracene, phenanthrene because of its difference structure bring the different distribution, the phenanthrene was easy to Tranthrough the cell membrane into the cytosol, thus react with macro-molecule and forms finally poisonous effect. But anthracene as it bigger distribution coefficient, beneficiation in the cellmembrane, and may cause themembrane toxicity.The interactions between o-tolidine (OT),2-naphthylamine-1-sulfonic acid (NS) and bovine serum albumin (BSA) were studied by spectrofluorimetry. Thebinding constants of OT,NS with BSA were measured at different temperatures. The effects of various pH and ionic strength on the binding constants of OT,NS with BSA were also studied. Thermodynamic parameter enthalpy changes (AH) and entropy changes (AS) were calculated according to the Vant'Hoff equation. The spectral results indicated that the binding of OT, NS to BSA induced conformational changes in BSA. The binding distances between OT,NS and the proteins were evaluated on the basis of the theory of Forster's energy transfer.