Oxidation of Zinc-Sulfur Centers by Reducible Organoselenium Compounds: A Review and Bonding Perspective

One potential mechanism for the effectiveness of organoselenium compounds against a number of cancer cell lines is the interaction of selenium with zinc signaling processes. Reducible selenium (rSe) compounds such as diselenides, selenenyl halides and seleninic acids release zinc from zinc fingers and metallothionein. Based upon a review of the literature, two key mechanisms are discussed: the stoichiometric displacement of zinc by selenium and the catalytic oxidation of Cys thiolates by reducible organoselenium compounds produced in situ. Initial DFT calculations of the strengths of interactions between rSe and a Cys2His2-type ZF model are presented to contrast the reactivity of reducible selenium compounds with sulfur and tellurium analogues.