INTERACTIONS OF HUMAN SERUM ALBUMIN WITH A PALLADIUM(II) COMPLEX CONTAINING A THIOAMIDE MOIETY: DETAILED EXPERIMENTAL AND MOLECULAR DOCKING STUDIES

Abstract

Thioamides and their derivatives are an interesting group of compounds because of their structural variations and also because of the combination of hard and soft donor atoms (S and N) that potentially allow coordination – in a variety of binding modes – to a wide range of metal centers, and also because of their biological significance. In our previous studies, we have synthesized a palladium(II) complex with a thioamide-type ligand of the formula [PdL2Cl2] (L= ethyl 4-[1-amino-2-cyano-3-(methylamino)-3-thioxo-1-propen-1-yl]-1-piperazine-1-carboxylate), whose ability to interact with DNA was investigated fluorometrically. In this work, research was continued in the direction of studying the interactions of the thioamide ligand and its palladium(II) complex with human serum albumin (HSA) in the presence of site-specific markers: warfarin (site I, subdomain IIA), ibuprofen (site II, subdomain IIIA) or methyl orange (site III, subdomain IB), to determine the binding affinity, binding strength and the location of binding site. The results obtained showed that ligand and complex bind moderately to the HSA via site III (subdomain IB), and that the quenching mechanism is static