Aurothionein formation from Zn,Cd-thionein and Et3PAuCl,but not Et3PAuSATg (auranofin)

Et₃PAuCl reacts in vitro with horse-kidney zinc, cadmium-metallothionein (Zn, CdTh) to displace zinc, but not cadmium. The ratio of gold-bound to zinc displaced is larger than that observed for gold sodium thiomalate (AuSTm), suggesting a different mode of binding. Et₃PAuSATg (Auranofin: 2,3,4,6- tetra-O-acetyl-1-thio-β-D-glucopyranosato(triethyl- phosphine)gold(I)), a new antiarthritic compound, does not react with Zn, CdTh. The significance of the nonreaction of Et₃PAuSATg, in contrast to Et₃PAuCl and AuSTm (previously studied), for the in vivo pharmacology of gold is discussed.