Study on the interaction between typical phthalic acid esters (PAEs) and human haemoglobin (hHb) by molecular docking

This work has evaluated the binding force between hHb and typcial PAEs (DMP, DEP, DPRP, DBP, DIBP, DHP and DPHP) using molecule docking technique. The DPHP with 3 aromatic rings has the strongest binding (-ΔG_binding: 6.0kcalmol^-1) than other PAEs (-ΔG_binding: 2.91∼4.48kcalmol^-1). The DMP with the lowest molecular weight has a high binding force (-ΔG_binding: 4.48kcalmol^-1), while the DHP with the highest molecular weight has the lowest binding force (-ΔG_binding: 2.91kcalmol^-1). When the length of side chain increases, the binding force trend to decrease, regarding the VDW forces and H-bonding. The lgK_ow-ΔG_binding plotting figure shows that a higher K_ow value is accompanied by a lower binding force. The aromatic ring existed in PAEs largely increases the binding force between the hHb and the PAEs. On the other hand, the PAEs with higher number of carbon, meaning a higher hydrophobicity, can enter into the hydrophobic space of hHb centre deeper and bond to different position. The aromatic ring decreases the depth of binding position in the hydrophobic space. This work provides basic data and a theoretical method to assess the transport and accumulation of PAEs in human body, and the cytotoxicity of PAEs to hBRCs.